Pressure testable hydraulically activated wellbore tool

ABSTRACT

A wellbore tool is provided that can withstand applied pressure tests without becoming hydraulically actuated. The wellbore tool includes a tubular housing including an inner bore; a tool mechanism responsive to fluid pressure; and an indexing mechanism that indexes responsive to tubing pressure cycles of at least an indexing pressure. The indexing mechanism is configured to activate the tool mechanism after a preset number of indexes. The wellbore tool can be pressure tested at pressures above an activation pressure without activating the tool mechanism.

RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent Application 62/184,765, entitled “Wellbore Tool With Indexing Mechanism and Method,” filed Jun. 25, 2015 and U.S. Provisional Patent Application No. 62/334,877, entitled “Pressure Testable Hydraulically Activated Wellbore Tool,” filed May 11, 2016, each of which is fully incorporated by reference herein.

TECHNICAL FIELD

This disclosure relates to systems and methods for wellbore tools. More particularly, embodiments described herein relate to pressure testable wellbore tools. Even more particularly, embodiments of the present disclosure relate to pressure testable hydraulically activated wellbore tools.

BACKGROUND

Completion of an oil or gas well often involves inserting a tubing string into the well. The tubing string carries various tools and functions as a flow path for cement, stimulation fluids and other fluids into the well and for production of hydrocarbons from the well. To ensure that the tubing string will maintain structural integrity against the pressures and pressure cycles that it will encounter during its functional life, an operator will often pressure test the tubing string after installation. The operator's ability to pressure test the tubing string may be limited however by the tools that make up the string. In particular, an operator's ability to pressure test a tubing string may be limited by hydraulically actuated tools, which are prone to prematurely activating during pressure tests.

It is common practice to provide a toe port tool with hydraulically openable ports near the bottom or “toe,” end of the tubing string. Conventionally, toe port tools are located at least 100 ft. from the toe (typically 100 ft-400 ft.) from the toe to ensure that they do not become contaminated with cement. Conventional hydraulically actuated toe port tools typically include a sliding sleeve that may be acted upon by tubing pressure (combined hydrostatic pressure and applied pressure) to move the sleeve from a port covering position to a port open position. More particularly, many hydraulically actuated toe port tools are based on the concept of providing opposed piston faces on the sliding sleeve such that raising tubing pressure will create a sufficient net force to move the sliding sleeve. During actuation, one of the piston faces is exposed to tubing pressure while the other is exposed to an atmospheric chamber. The pressure differential causes the sleeve to shift to the port open position. In doing so, the sleeve shifts further into the atmospheric chamber, reducing the chamber's volume.

Conventional toe port tools typically have limited pressure test capability. During pressure testing, the ports of the toe port tool should remain closed so that pressure can be increased in the tubing string. However, because the toe port tool is relatively deep in the well, the hydrostatic pressure may already be near the activation pressure threshold or even operational pressure limit of the toe port tool. The applied pressure asserted during pressure testing must remain relatively low or else pressure testing risks prematurely opening the toe port tool or damaging the toe port tool. While some mechanisms have been proposed to allow a toe port tool to be pressure tested at or above the activation pressure without opening, such mechanisms lack redundancy and provide for a relatively limited number of pressure cycles before the tool is activated.

Moreover, many conventional hydraulically actuated toe port tools have limited pressure capability. For example, common hydraulically actuated toe port tools used in the industry for standard casing sizes 4.5-5.5 typically have an absolute pressure rating of 10,000-20,000 psi and a differential pressure rating of 10,000-18,000 psi. One reason for this is that, in some designs, the wall adjacent to the atmospheric chamber is relatively thin to provide space for the sleeve to move. Because of the high pressures in and around the toe port tool, the walls of the toe port tool adjacent to the atmospheric chamber may experience substantial differential pressures that can cause the walls to flex or buckle. This deformation may prevent the sleeve from opening properly.

Furthermore, conventional hydraulically actuated toe port tools risk damaging themselves or the tubing strings in which they are installed. Many toe port tools include rupture disks or shear pins so that the sleeve will not move until the tubing pressure reaches a predetermined activation pressure. Due to the extreme difference between tubing pressure and the pressure in atmospheric chambers, the sudden application of tubing pressure to a sleeve or release of the sleeve from shear pins can result in a sleeve opening violently, potentially damaging the toe port tool, breaking connections or otherwise damaging the string.

SUMMARY

In accordance with one aspect of the preset disclosure, a pressure testable well bore tool is provided. The wellbore tool can include a tubular housing having an inner surface and an outer surface, with the inner surface defining a central bore. The wellbore tool can further include a tool mechanism responsive to hydraulic pressure. The wellbore tool can further include an indexing mechanism that indexes responsive to tubing pressure cycles of at least an indexing pressure. According to one embodiment, the indexing pressure may be adjustable such that, for example, the indexing pressure can be defined for a number of tubing pressure test cycles. The indexing mechanism is configured to activate the tool mechanism after a preset number of indexes. The wellbore tool can be pressure testable at pressures above an activation pressure without prematurely activating the tool mechanism. According to one embodiment, the wellbore tool can be testable without activating the tool mechanism for a number of tubing pressure test cycles.

In accordance with another embodiment, the wellbore tool can include a tubular housing having an inner surface and an outer surface, with the inner surface defining a central bore. The wellbore tool can further include a tool mechanism responsive to hydraulic pressure. The wellbore tool can further include an indexing mechanism that indexes responsive to tubing pressure cycles of at least an indexing pressure. The indexing mechanism may include an activation mechanism adapted to punch an opening in a device, such as a rupture disk or other device, to activate the tool mechanism. According to one embodiment, the wellbore tool can be testable without activating the tool mechanism for a number of tubing pressure test cycles.

In accordance with another embodiment, the wellbore tool can include a tubular housing having an inner surface and an outer surface, with the inner surface defining a central bore. The wellbore tool can further include a tool mechanism responsive to hydraulic pressure. The wellbore tool can further include redundant indexing mechanisms responsive to tubing pressure cycles of at least an indexing pressure. The indexing pressure of each redundant indexing mechanism may be the same or may be different. Each indexing mechanism can be configured to activate the tool mechanism after a preset number of indexes. The wellbore tool can be pressure testable at pressures above an activation pressure without prematurely activating the tool mechanism.

According to one embodiment, an indexing mechanism can comprise an index counter. The index counter may include a ratchet mechanism that defines a plurality of indexing positions. The ratchet mechanism can include a movable ratchet and an indexing member translatable in an indexing mechanism bore through the plurality of indexing positions from an initial indexing position to a final indexing position. According to one embodiment, the final indexing position can be proximate an activation mechanism. In accordance with one embodiment, the index counter may be disposed in a sealed chamber, such as an atmospheric chamber or other reference pressure chamber during indexing.

The indexing mechanism may further include an indexing piston adapted to incrementally advance the indexing member in a first direction, through a series of pressure responsive actuations, from the initial indexing position to the final indexing position. The indexing piston may also be adapted to move the indexing member from the final indexing position to push an activation member (e.g., an activation pin) to activate the tool.

The ratchet mechanism, in some embodiments, may further comprise a first indexing profile disposed on an inner wall surface of an indexing mechanism bore. The movable ratchet may have a second indexing profile. The indexing member can be disposed between the inner wall surface and the movable ratchet. The indexing member can have an outer surface with a third indexing profile selected to engage the first indexing profile and an inner surface with a fourth indexing profile selected to engage the second indexing profile. The first indexing profile, second indexing profile, third indexing profile and fourth indexing profile are selected such that the indexing member is movable with the movable ratchet in the first direction and is stopped against movement with the movable ratchet in a second direction.

The indexing mechanism may change from an indexing configuration to an activation configuration upon reaching the preset number of indexes. In the activation configuration, the indexing mechanism is responsive to the activation pressure to activate the tool mechanism. The activation pressure may be the same as the indexing pressure.

According to one embodiment, an indexing mechanism may include a biasing member that biases the indexing mechanism against pressure applied to the indexing mechanism. The indexing mechanism may also include a hydrostatic preloader that can preload the biasing member to set the indexing pressure. The hydrostatic preloader may be adjustable such that the indexing pressure is adjustable.

According to one aspect, the indexing mechanism may include an activation mechanism. The activation mechanism may include an activation member movable from an initial position to an activation member second position. The indexing piston can be adapted to move the indexing member to activate the activation mechanism. In one embodiment, the indexing piston can be adapted to move the indexing member from an indexing location corresponding to the preset number of indexes to push the activation member to the activation member second position. In one embodiment, the activation member is adapted to shift to punch through a device. By way of example, but not limitation, the activation member may pierce or otherwise remove a seal.

The activation mechanism can be adapted to open a flow path through the indexing mechanism bore when activated. According to one aspect, the indexing mechanism is configured to isolate the tool mechanism from the central bore to prevent the tool mechanism from prematurely activating and to activate the tool mechanism after the preset number of indexes by opening the flow path through the indexing mechanism to fluidly connect the central bore to the tool mechanism.

In one embodiment, the activation mechanism further comprises a locking member. The locking member can be configurable between at least (i) a locked out configuration in which the locking member is locked out against an inner surface of the indexing mechanism bore and prevents the indexing piston from breaking a seal formed by a piston seal between the indexing piston and a piston seal surface; and (ii) a collapsed piston release configuration that does not prevent the indexing piston from actuating a distance sufficient to break the seal formed between the indexing piston and the piston seal surface by the piston seal. The locking member is adapted to change from the locked out configuration to the piston release configuration responsive to movement of the activation member from the activation member initial position to the activation member second position. The indexing piston can be adapted to break the seal formed between the indexing piston and the piston seal surface by the piston seal and drive the activation member to remove the activation mechanism seal to unseal the flow path through the indexing mechanism bore.

In accordance with one embodiment, the wellbore tool comprises a plurality of independently operating indexing mechanisms. In some cases, the independently operating indexing mechanisms are each configured activate the tool mechanism after the preset number of indexes.

According to one embodiment, the wellbore tool may be a ported tool, such as a toe port tool, or other ported tool. The tubular housing may have one or more ports through the housing wall that are openable to connect the central bore to the outer surface. The tool mechanism can comprise a sliding sleeve slidable from a port closed position blocking the one or more ports to a port open position at least partially retracted from the one or more ports. In some embodiments, the slidable sleeve may be slidable in an annular space between a mandrel and an outer housing.

Prior to activating the tool, the indexing mechanism may be configured to isolate the tool mechanism from the central bore to prevent the tool mechanism from prematurely activating. The indexing mechanism may be configured to activate the tool mechanism after the preset number of indexes by opening a flow path from the central bore to the tool mechanism. In one embodiment, the indexing mechanism is configured to activate the tool mechanism by opening a flow passage to fluidly connect the tool's central bore to a piston face of the sliding sleeve.

In one embodiment, the wellbore tool has a non-activated configuration in which a first piston face of the sliding sleeve is exposed to a first pressure chamber that is isolated from the central bore. In some embodiments, the sliding sleeve may comprise a second piston face, wherein in the non-activated configuration, the second piston face is exposed to tubing pressure. The indexing mechanism can be configured to activate the sliding sleeve by opening the flow passage to fluidly connect the first pressure chamber to the central bore.

The wellbore tool may further include a compensation piston disposed in an annular space. The compensation piston may have a first piston face exposed to a second pressure chamber and a second piston face fluidly connected to the central bore. The compensation piston may be slidable in the annular space to compensate for pressure changes. The wellbore tool may further include a spring that biases the sliding sleeve toward a port open position, wherein the sliding sleeve is slidable to balance forces from the pressure in the first pressure chamber with forces from the spring and pressure in the second pressure chamber. The first pressure chamber and second pressure may be filled with hydraulic fluid.

According to another aspect, a method for testing a downhole tool is provided. The method may include installing a wellbore tool in a wellbore. According to one embodiment, the wellbore tool is installed adjacent to a distal end of a tubing string. The wellbore tool can comprise an indexing mechanism configured to index pressure cycles of at least an indexing pressure and activate the wellbore tool after a preset number of indexes. Prior to installing the wellbore tool at the location in the wellbore, an adjustable indexing pressure of the indexing mechanism can be set to be at least a hydrostatic pressure at the location. One or more pressure tests of the tubing string can be conducted by applying one or more test pressures to the tubing string pressure at the wellbore tool during the one or more pressure tests is above the indexing pressure for the indexing mechanism. After completion of the one or more pressure tests, pressure can be applied to the tubing string to complete remaining index cycles and activate the wellbore tool. The pressure applied to the tubing string to activate the wellbore tool can be lower than the one or more test pressures.

According to another embodiment, a method may comprise: installing the wellbore tool in the wellbore, conducting one or more pressure tests of the tubing string by applying one or more test pressures to the tubing string such that a tubing pressure at the wellbore tool during the one or more pressure tests is above the indexing pressure for the wellbore tool and after completion of the one or more pressure tests, applying pressure to the tubing string to complete remaining index cycles and to punch an opening in a device using the indexing mechanism to activate the wellbore tool. The pressure applied to the tubing string to activate the wellbore tool may be lower than the one or more test pressures.

Another embodiment may include installing a wellbore tool in a wellbore where the wellbore tool comprises redundant indexing mechanisms configured to index pressure cycles of at least an indexing pressure and activate the wellbore tool after a preset number of indexes. The method may further include conducting one or more pressure tests of the tubing string by applying one or more test pressures to the tubing string such that a tubing pressure at the wellbore tool during the one or more pressure tests is above the indexing pressure. After completion of the one or more pressure tests, pressure may be applied to the tubing string to complete remaining index cycles of at least one indexing mechanism and activate the wellbore tool. The pressure applied to the tubing string to activate the wellbore tool may be lower than the one or more test pressures.

According to another aspect, a method for testing a downhole tool is provided. The method may include installing a wellbore tool in a wellbore. According to one embodiment, the wellbore tool is installed adjacent to a distal end of a tubing string. The wellbore tool can comprise an indexing mechanism configured to index pressure cycles of at least an indexing pressure and activate the wellbore tool after a preset number of indexes; conducting one or more pressure tests of the tubing string by applying one or more test pressures to the tubing string such that a tubing pressure at the wellbore tool during the one or more pressure tests is above the indexing pressure for the wellbore tool; and after completion of the one or more pressure tests, applying pressure to the tubing string to complete remaining index cycles and activate the wellbore tool, wherein the pressure applied to the tubing string to activate the wellbore tool is lower than the one or more test pressures.

The method may further comprise configuring the indexing mechanism prior to installing the wellbore tool such that the indexing pressure is at least a hydrostatic pressure at a location in the wellbore where wellbore tool is to be installed.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings accompanying and forming part of this specification are included to depict certain aspects of the invention. A clearer impression of the invention, and of the components and operation of systems provided with the invention, will become more readily apparent by referring to the exemplary, and therefore nonlimiting, embodiments illustrated in the drawings, wherein identical reference numerals designate the same components. Note that the features illustrated in the drawings are not necessarily drawn to scale.

FIG. 1 is a diagrammatic representation of a cross-sectional view of one embodiment of an indexing device.

FIG. 2 is a diagrammatic representation of cross-sectional views of one embodiment of a ratcheting mechanism.

FIG. 3 is a diagrammatic representation of cross-sectional views of one embodiment of a ratcheting mechanism.

FIG. 4 is a diagrammatic representation of a cross-sectional view of one embodiment of an activation mechanism in a first configuration.

FIG. 5 is a diagrammatic representation of a cross-sectional view of one embodiment of an activation mechanism in a second configuration.

FIGS. 6 is a diagrammatic representation of a cross-section view of an indexing mechanism with another embodiment of an activation mechanism in a first configuration.

FIG. 7 is a diagrammatic representation of a cross-section view of an indexing mechanism with another embodiment of an activation mechanism in a second configuration.

FIG. 8 is a diagrammatic representation of a cross-section view of an indexing mechanism with another embodiment of an activation mechanism in a third configuration.

FIG. 9 is a diagrammatic representation of one embodiment of a portion of an indexing mechanism.

FIG. 10 is a diagrammatic representation of one embodiment of a portion of an indexing mechanism illustrating a piston seal at a first position.

FIG. 11 is a diagrammatic representation of one embodiment of a portion of an indexing mechanism illustrating a piston seal at a second position.

FIG. 12 is a diagrammatic representation of one embodiment of a portion of an indexing mechanism illustrating a piston seal at a third position.

FIG. 13 is a diagrammatic representation of a cross-sectional view of one embodiment of a ported wellbore tool.

FIG. 14 is a diagrammatic representation of a cross-sectional view of one embodiment of an opening assembly in a first configuration.

FIG. 15 is a diagrammatic representation of a cross-sectional view of one embodiment of an opening assembly in a second configuration.

FIG. 16 is a diagrammatic representation of a cross-sectional view of one embodiment of a portion of a ported wellbore tool.

FIG. 17 is a diagrammatic representation of a cross-sectional view of one embodiment of a ported wellbore tool with redundant indexing mechanisms.

FIG. 18 is a diagrammatic representation of a cross-sectional view of another embodiment of an indexing device.

FIG. 19 is a diagrammatic representation of a cross-sectional view of yet another embodiment of an indexing device.

FIG. 20 is a diagrammatic representation of a cross-sectional view of yet another embodiment of an indexing device.

FIG. 21 is a diagrammatic representation of a cross-sectional view of another embodiment of an indexing device.

FIG. 22 is a diagrammatic representation of a cross-sectional view of another embodiment of an indexing device.

FIG. 23 is a diagrammatic representation of a cross-sectional view of another embodiment of an indexing device.

FIG. 24 is a diagrammatic representation of one embodiment of a tubing string.

FIG. 25A is a diagrammatic representation of a portion of one embodiment of an indexing device in a first configuration.

FIG. 25B is a diagrammatic representation of a portion of one embodiment of an indexing device in a second configuration.

DETAILED DESCRIPTION

The invention and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known starting materials, processing techniques, components and equipment are omitted so as not to unnecessarily obscure the invention in detail. It should be understood, however, that the detailed description and the specific examples, while indicating some embodiments of the invention, are given by way of illustration only and not by way of limitation. Various substitutions, modifications, additions and/or rearrangements within the spirit and/or scope of the underlying inventive concept will become apparent to those skilled in the art from this disclosure.

When used with reference to the figures, unless otherwise specified, the terms “upwell,” “above,” “top,” “first,” “downwell,” “below,” “bottom,” “lower,” and like terms are used relative to the direction of normal production and/or flow of fluids and or gas through the tool and wellbore. Thus, normal production results in migration through the wellbore and production string from the downwell to upwell direction without regard to whether the tubing string is disposed in a vertical wellbore, a horizontal wellbore, or some combination of both. Similarly, during the fracing process, fracing fluids and/or gasses move from the surface in the downwell direction to the portion of the tubing string within the formation.

Oil and gas operations regularly require tubing strings and equipment mounted in such tubing strings (packers, sliding sleeve subs, barrier valves, etc.) to be subjected to pressure tests. In some cases, a tubing string may have to be pressure tested multiple times. Embodiments described herein provide systems and methods that allow a wellbore tool to be subjected to multiple pressure test cycles without prematurely activating. Moreover, the pressure tests can be performed at pressures that are higher than the activation pressure of the wellbore tool.

In accordance with the present disclosure, a wellbore tool can be provided with an indexing mechanism that participates in activating the tool. The indexing mechanism can be pressure actuated, but set up not activate the tool until a predetermined number of pressure cycles have been applied. The indexing mechanism can prevent pressure cycles, including pressure cycles above the activation pressure from the tool from activating the tool until a predetermined pressure cycle, at which point the indexing mechanism can activate the tool. The indexing mechanism can allow an operator to pressure test the tool at pressures greater than the activation pressure without activating the tool until the predetermined pressure cycle.

The indexing mechanism can be adapted to activate a wellbore tool, but can be configured not activate the tool until after the indexing mechanism has indexed a preset number of times. The indexing mechanism can index responsive to pressure cycles that satisfy a threshold indexing pressure requirement. Until the indexing mechanism has indexed the preset number times the indexing mechanism can be in an indexing configuration whereby, pressure cycles that meet or exceed the indexing pressure requirement are registered by the indexing mechanism but will not cause the indexing mechanism to activate the tool, even if the pressure applied to the tool exceeds an activation pressure for the tool. Prior to reaching the preset number of indexes, the indexing mechanism can prevent pressure cycles from activating the tool. For example, the indexing mechanism can be configured to isolate the tool or portion of the tool from tubing pressure so that test pressures applied through the tubing string cannot activate the tool. An operator can pressure test the tool at pressures greater than the activation pressure without activating the tool until the indexing mechanism indexes the preset number of times. After the indexing mechanism has indexed the preset number of times, the indexing mechanism can have an activation configuration whereby a pressure cycle of at least an activation pressure (which may be the same as the indexing pressure) can cause the indexing mechanism to activate the tool.

In accordance with one embodiment, the indexing mechanism includes an index counter with an indexing member that can translate along a bore through a plurality of indexing positions with the final indexing position located proximate to an activation mechanism. The indexing mechanism can include a piston that actuates responsive to pressure cycles that satisfy a threshold indexing pressure requirement. When the piston actuates, the piston can push the indexing member to the next indexing position. The piston incrementally advances the indexing mechanism toward the activation mechanism with each pressure cycle that it registers. After a preset number of indexes, the indexing member will be proximate to the activation mechanism. Upon the next actuation, the piston can push the indexing member onto the activation mechanism to activate the tool. According to one embodiment, the activation mechanism may punch an opening in a device to activate the tool.

While embodiments described herein may be utilized with a variety of wellbore tools, they may be particularly helpful when used in conjunction with toe port tools, which are often subjected high hydrostatic pressures. The indexing mechanisms can be installed in small diameter holes such that any atmospheric chambers used in the indexing mechanism may be small diameter, high pressure atmospheric chambers, including pressure chambers having a pressure rating of greater than 30,000 psi. Thus, indexing mechanisms can be incorporated into toe port tools without compromising the pressure rating of the tool. Furthermore, an indexing mechanism can be set up to have a high indexing pressure that accounts for the high hydrostatic pressures experienced by some toe port. The indexing pressure can be such that hydrostatic pressure will not inadvertently cycle the indexing mechanism and so that some amount of pressure must be applied over the hydrostatic pressure to index the indexing mechanism.

One example of a wellbore tool that can incorporate an indexing mechanism is a hydraulically activated ported tool, such as a toe port tool (sometimes referred to as a “toe sleeve”). In one embodiment of a hydraulically activated ported tool, an indexing mechanism can be operatively coupled to a sliding sleeve and be configured not to activate the sliding sleeve until the indexing mechanism has indexed a preset number of times. Prior to reaching the preset number of indexes the indexing mechanism can prevent pressure cycles from activating the tool. For example, the indexing mechanism may isolate a portion of the tool from the tool's central bore to prevent activation. After the indexing mechanism has indexed the preset number of times, the indexing mechanism can be responsive to the next application of sufficient pressure to activate the tool. The indexing mechanism can open one side of the sliding sleeve to higher or lower pressure to move the sleeve to a port open position. For example, the indexing mechanism may rupture a seal, open a flow passage through the indexing mechanism or take some other action to expose the side of the sleeve to the central bore, thereby activating the sleeve.

Embodiments described herein also provide a hydraulically activated ported tool that has high pressure capability. In accordance with one embodiment, the hydraulically activated ported tool may include a spring biased pressure compensated sleeve in which the sleeve is acted upon by pressure in chambers above and below the sleeve. The hydraulically activated ported tool may further include an indexing mechanism operatively coupled to the sleeve. The indexing mechanism can be configured to activate the sleeve after a preset number of pressure applications at or above an indexing pressure. Prior to indexing a preset number of times, the indexing mechanism may isolate a portion of the tool from the tool's central bore to prevent the sleeve from activating. After the preset number of pressure applications, the indexing mechanism, in response to an additional application of pressure or other trigger, can open and vent a pressure chamber on one side of the sleeve, allowing the spring to open the sleeve.

According to one embodiment, the chambers above and/or below a sliding sleeve can be pressure compensated chambers that can be maintained at or near the tubing pressure. As a result, the pressure differential across the inner and outer walls adjacent to the pressure compensated chambers may be relatively small when compared to atmospheric chambers. The pressure compensated chambers, in some embodiments, may be oil (or other liquid) filled. Because liquid is less compressible than gas, the liquid will better prevent the walls from deforming compared to an atmospheric chamber. Therefore, a hydraulically activated ported tool can be configured to achieve a high absolute pressure rating.

Moreover, one embodiment of a hydraulically activated ported tool can incorporate small diameter indexing mechanisms with high pressure ratings. Such embodiments can thus provide a high pressure rated ported tool that can be pressure tested multiple times prior to activation.

Embodiments described herein can include features that contribute to reliability. Components of the indexing mechanism may be disposed in a sealed chamber, such as an atmospheric chamber or other reference pressure chamber during indexing. According to one embodiment, for example, the index counter of the index mechanism is sealed from the central bore and annulus and is thus protected and is thus protected from well fluid that can that adversely affect the functioning of an indexer. Furthermore, in some embodiments the indexing mechanism activates the wellbore tool by punching an opening in a device, such as a rupture disk or other device. This mechanism is believed to be more resilient and less error-prone, especially in high pressure and temperature applications (for example, as experienced at toe ports) than solutions that use a sliding sleeve piston to reveal an opening in order to activate a tool. Moreover, some embodiments may include redundant indexing mechanisms that are tuned to respond to approximately the same pressure thresholds. If one of the redundant indexing mechanisms fails, another indexing mechanism can operate to activate the tool.

FIG. 1 is a diagrammatic representation of one embodiment of an indexing device 100 that allows a tool to be pressure tested multiple times at pressures greater than the pressure required to activate the tool. Indexing device 100 may be used in conjunction with a variety of tools including, but not limited to, toe port tools, packers and other tools.

Indexing device 100 includes a housing 101 that houses indexing mechanism 103. Housing 101 can take various forms. According to one embodiment, housing 101 may comprise the walls of a sub or other tool in which an indexing mechanism 103 is installed. In other embodiments, indexing device 100 may be formed as a cartridge with an independent housing that can be inserted in a hole in a tool wall or elsewhere in a tool. Housing 101, in cooperation with components of indexing mechanism 103, defines an indexing mechanism inner bore 104 that extends from a first end 106 a to a second end 106 b. First end 106 a and second end 106 b may be adjacent to or fluidly connected to areas or components of a wellbore tool so that indexing device 100 can activate the tool.

Indexing mechanism 103 includes an indexing piston 110, an index counter 145 and an activation mechanism 200 operatively coupled to index counter 145. Indexing piston 110 is adapted to actuate responsive an energy source and drive index counter 145. After a number of indexes of index counter 145, activation mechanism 200 operates to cause a tool to change states such that the tool activates.

In accordance with one embodiment, index counter 145 comprises a ratchet mechanism having an indexing member 112 that is adapted to be translated along inner bore 104 through a plurality of indexing positions. When piston 110 actuates in a first direction (toward activation mechanism 200 in the embodiment illustrated) piston 110 can move indexing member 112 to the next indexing position, thereby incrementing index counter 145. Through a series of actuations, piston 110 incrementally advances indexing member 112 through the plurality of indexing positions toward activation mechanism 200. After a predetermined number of indexes, indexing member 112 will be in a final indexing position proximate to activation mechanism 200. Upon the next actuation, piston 110 can push indexing member 112 against activation pin 114 of activation mechanism 200 to shift activation pin 114 in order to activate a tool. Activation pin 114 can puncture a rupture disk, remove a plug, trigger an electronic component, detonate a charge or otherwise cause a tool to change state such that the tool activates. Indexing piston 110 can be adapted to actuate responsive to pressure. Indexing piston 110 can include a piston head portion 115 with an indexing piston face 120 that can be exposed to tubing pressure or other piston driving pressure source. An indexing piston seal 118 is provided between piston 110 and an inner surface of bore 104. Indexing piston seal 118, according to one embodiment, cooperates with activation mechanism seal 203 or other seal to form a reference pressure chamber 122, such as an atmospheric chamber, and isolates reference pressure chamber 122 from indexing piston face 120. The application of pressure to indexing piston face 120 can establish a pressure differential across seal 118 to actuate piston 110 in a first direction. A biasing member may bias indexing piston 110 in the opposite direction such that the pressure applied to indexing piston face 120 must be at least a threshold indexing pressure in order to actuate indexing piston 110 an indexing distance (a distance sufficient to index indexing member 112). In the embodiment depicted, a compression spring 124 (e.g., a Bellville spring or other suitable spring) is provided in reference pressure chamber 122 to bias indexing piston 110. Compression spring 124 presses on a shoulder 126 of movable spacer sleeve 117 of indexing piston 110 and biases indexing piston 110 toward an initial position.

Piston 110 may thus actuate in a first direction in response to tubing pressure (or other pressure source) that is at least the indexing pressure. As piston 110 actuates in the first direction, piston 110 can carry indexing member 112 in that direction. Spring 124 can bias piston 110 back to an initial position when the pressure on indexing piston face 120 drops below the indexing pressure. Index counter 145 can be configured, however, such that indexing member 112 does not move back on the return stroke. The piston 110 thus incrementally advances indexing mechanism 112 through the indexing positions and toward the activation mechanism 200 with each pressure cycle that it registers. It can be noted that relative position of indexing member 112 corresponds to a count of the number of pressure cycles above the indexing pressure that indexing mechanism 103 registered. After a predetermined number of indexes, piston 110 can actuate to activate activation mechanism 200.

Piston face 120 may be exposed to tubing pressure such that the tubing pressure can be cycled to actuate piston 110 and cycle index counter 145. As one of ordinary skill in the art will appreciate, hydrostatic pressure may be a large component of the pressure asserted on piston face 120 in this situation and will depend on the location of indexing device 100 in the tubing string. Indexing mechanism 103 may have an adjustable indexing pressure to compensate for hydrostatic pressure or other pressure. Indexing device 100, according to one embodiment, can include a hydrostatic preloader to preload the biasing member such that the indexing pressure is a pressure greater than the hydrostatic pressure. Accordingly, indexing mechanism 103 can be configured so that hydrostatic pressure will not cause accidental indexing. Spring 124 or other biasing member may also be preloaded to filter out pressure variations above hydrostatic pressure so that, for example, small pressure variations above hydrostatic pressure do not cycle indexing mechanism 103.

The hydrostatic preloader, in one embodiment, can set the initial compression in spring 124 such that indexing piston 110 will not actuate due to anticipated hydrostatic pressure. Various mechanisms may be used to preload spring 124. Indexing piston 110 may include a shaft with a threaded connection, telescoping connection or other connection between portions of the shaft such that the length of indexing piston 110 may be changed to change the initial compression in spring 124. According to one embodiment, for example, piston 110 includes shaft 111 that passes through spacer sleeves 117 and 149 and is connected to ratchet 150 at ratchet connector 199. As illustrated in more detail in FIGS. 2-3, shaft 111 can be threaded to a ratchet connector 199 at a threaded connection 151. Ratchet connector 199 is threaded to or otherwise coupled to a ratchet 150. By selecting the depth of engagement of shaft 111 in threaded connection 151, the length of indexing piston 110 can be selected. By changing the length of the indexing piston 110 from piston head portion 115 to the ratchet connector 199, spring 124 may be compressed to a desired level of initial compression, thereby setting the preload.

In another embodiment, one or more tubular components of indexing mechanism 103 can act as a hydrostatic preloader. In one embodiment, for example, first end tubular 128 in cooperation with piston head seal tubular 134 can provide a hydrostatic preloader that is adjustable to compensate for anticipated hydrostatic pressure. In the embodiment illustrated, first end tubular 128 can be threaded into housing 101 to a selected depth. End tubular 128 pushes on piston head seal tubular 134, which in turn pushes on shoulder 136 of indexing piston 110. Indexing piston 110, in turn, compresses spring 124 (e.g., at shoulder 126). By adjusting the depth of first end tubular 128 the initial compression of spring 124 can be set such that some amount of pressure above the anticipated hydrostatic pressure is required to actuate indexing piston 110 an indexing distance. One of ordinary skill in the art would recognize that spring 124 may also be preloaded in other suitable ways.

With further reference to FIG. 1, stroke limiter 180 limits the indexing stroke of indexing piston 110 such that piston 110 will travel a known amount regardless the pressure applied to piston face 120 (assuming the pressure applied is at least the indexing pressure). Consequently, piston 110 advances indexing member 112 a predefined amount regardless of the actuation pressure. Stroke limiter 180 can prevent over indexing when the pressure asserted on indexing piston 110 exceeds the indexing pressure and thus helps prevent piston 110 from prematurely activating activation mechanism 200 when higher pressures are applied (such as in pressure tests).

Moreover, stroke limiter 180 can provide a short indexing travel that ensures relative movement within indexing mechanism 103 is limited and significantly reduced over J-type indexing mechanisms. In some embodiments, the indexing travel can be approximately an inch, but smaller or larger lengths are possible depending on configuration.

Furthermore, incorporating spring 124 or other energy source, in combination with a predefined stroke length, indexing device 100 can be set up to only index within a preset operating window that can prevent unintended indexing and allows for accurate cycle counting.

FIGS. 2 and 3 are diagrammatic representations of one embodiment of an index counter 145. According to one embodiment, index counter 145 comprises a ratchet mechanism that includes an outer ratchet ring 135 that defines a portion of inner bore 104. Ratchet ring 135 includes an indexing profile 138 defined on an inner wall surface. Indexing piston 110 includes a ratchet 150 that has an indexing profile 152 defined on its outer surface. Ratchet 150 provides a moving ratchet structure that can reciprocate in bore 104. Indexing member 112 is disposed between ratchet 150 and ratchet ring 135. Indexing member 112, according to one embodiment, comprises a flexible c-ring, lock ring or other structure that has an outer surface facing the inner wall surface of bore 104 and an inner surface facing ratchet 150. The outer surface of indexing member 112 includes an indexing profile 158 to selectively engage indexing profile 138 and the inner surface of indexing member 112 includes an indexing profile 160 to selectively engage indexing profile 152.

The indexing profiles 138, 158, 152, 160 can be configured so that indexing member 112 moves with ratchet 150 when ratchet 150 moves in the first direction, but does not move with ratchet 150 when ratchet 150 moves in the second direction. Consequently, by relative movement between indexing piston 110 and ratchet ring 135, indexing member 112 moves in a first direction along ratchet ring 135 with each indexing stroke of ratchet 150 in the first direction but does not move back with ratchet 150 on the return stroke.

In one embodiment, indexing profile 138 comprises a first set of ratchet teeth with each tooth having a ridge with a moderately sloped side 162 sloped into a valley on one side and a steeply sloped side 164 sloped into the valley on the other side and indexing profile 158 comprises at least one pawl (tooth) having a ridge with a moderately sloped side 168 sloped into a valley on one side and a steeply sloped side 170 sloped into a valley on the other side. The moderately sloped sides 162 and 168 can face each other such that the teeth of indexing profile 138 and indexing profile 158 can easily pass over each other when indexing member 112 moves in the first direction, but steeply sloped sides 164 and 170 will catch to prevent indexing member 112 from moving relative to ratchet ring 135 in the second direction (to prevent indexing member 112 from moving back with ratchet 150 on the return stroke).

Furthermore, in one embodiment, indexing profile 152 comprises a second set of ratchet teeth with each tooth having a ridge with moderately sloped side 172 into a valley on one side and a steeply sloped side 174 into the valley on the other side and indexing profile 160 comprises at least one pawl (tooth) with each tooth having a ridge with a moderately sloped side 176 on one side and a steeply sloped side 178 on the other side. The moderately sloped sides 172 and 176 can face each other so that the steeply sloped sides 174 and 178 will catch when ratchet 150 moves in the first direction such that indexing member 112 travels with ratchet 150 in the first direction, but the teeth of indexing profile 152 and indexing profile 160 can pass over each other when ratchet 150 moves in the second direction. The ratchet teeth and pawl teeth may have a variety of profiles. In some embodiments ratchet teeth and pawl teeth may be formed by threads or wickers. According to one embodiment, the teeth may be arranged with teeth ridges and valleys substantially orthogonal to the axis of inner bore 104.

Stroke limiter 180 can be provided to limit the stroke of piston 110. In the embodiment illustrated, stroke limiter 180 comprises a shoulder 182 spaced from a facing shoulder 184 on indexing piston 110 and positioned to abut facing shoulder 184 when indexing piston 110 has moved a desired distance in the first direction. Stroke limiter 180 can be configured, for example, so that indexing piston 110 moves at least the length “L” of the teeth and less than 2 “L” such that each indexing position of indexing member 112 is “L” apart. According to one embodiment, stroke limiter 180 can limit the stroke of indexing piston 110 to 1.3-1.5 “L”. In other embodiments, the stroke limiter 180 can allow the stroke to be greater than 2 L, but such an embodiment would reduce the number of indexing positions for the same number of teeth and could result in partial indexing.

FIG. 2 illustrates one embodiment of index counter 145 with indexing member 112 in a starting position and FIG. 3 illustrates index counter 145 after indexing member 112 has moved to the final indexing position proximate to activating pin 114. In this embodiment, indexing mechanism 103 is configured not to activate a tool until after it has indexed six times (indexing member 112 must index six times to move from the start position illustrated in FIG. 2 to the final index position proximate to the activation mechanism illustrated in FIG. 3)

Prior to reaching the configuration of FIG. 3, indexing mechanism 103 may be an indexing configuration whereby pressure cycles that meet or exceed the indexing pressure requirement are registered by the indexing mechanism but do not cause the indexing mechanism to activate the tool, even if the pressure cycles exceed an activation pressure for the tool. Upon indexing the preset number of times—reaching the configuration of FIG. 3 in the illustrated embodiment—indexing mechanism 103 changes from an indexing configuration to an activation whereby a pressure cycle of at least an activation pressure (which may be the same as the indexing pressure) can cause the indexing mechanism to activate the tool.

With reference to FIG. 3, after six indexes, indexing mechanism 103 is in a configuration in which it will be responsive to an activation pressure to push indexing member 112 onto activation pin 114 and activate the activation mechanism 200. In some embodiments, the activation pressure may be higher than the indexing pressure. As discussed below, for example, movement of activation pin 114 may be restrained by releasable locking mechanisms (e.g., such as shear pins, c-rings, etc.) that assert a holding force on activation pin. A higher activation pressure than the indexing pressure may be required to overcome the holding force and shift activating pin 114 or otherwise activate an activation mechanism. In other embodiments, the application of indexing pressure to piston 110 may be sufficient to shift activating pin 114 or otherwise activate an activation mechanism.

FIGS. 4 and 5 are diagrammatic representations of a portion of indexing mechanism 103 proximate to second end 106 b (shown in FIG. 1) including an activation mechanism 200 and second end tubular 209. In the embodiment illustrated, activation mechanism 200 is an unloader assembly that comprises a tubular unloader module 202, a bushing 210, activation pin 114 and locking member 204. Activation pin 114 passes through locking member 204 and into a portion of inner bore 104 defined by unloader module 202. The nose of activation pin 114 carries an activation mechanism seal 203 that seals to the inner wall surface of bore 104 provided by unloader module 202. In an initial position prior to activation (shown in FIG. 4), activation pin 114 is positioned such that seal 203 seals with inner bore 104. It can be noted then that seal 203 may cooperate with piston seal 118 to seal chamber 122 such that indexing mechanism 103 may be run-in with the index counter 145 is disposed in a sealed chamber 122 (see FIG. 1).

Locking member 204 prevents activation pin 114 from prematurely activating and other components of indexing mechanism 103 from shifting in the first direction. According to one embodiment, locking member 204 comprises an inwardly biased ring having radial recesses 220 defined on its inner surface. Activation pin 114 includes projections 222 (e.g., shoulders, dogs or other projections) that provide areas of larger diameter. In an initial position, activation pin 114 supports locking member 204 on projections 222 such that locking member 204 is in a radially expanded, locked out, configuration. In the locked out configuration, locking member 204 locks against a portion of the inner surface of bore 104 and prevents various portions of indexing mechanism 103 from shifting. In one embodiment, locking member 204 may have external threads on the outer diameter and a portion of unloader module 202 may have threads on the inner bore. Locking member 204 can be threaded into the threaded inner bore of unloader module 202 such that the threads prevent translation when locking member 204 is in the locked out configuration. Shifting of locking member 204 may also be prevented by other mechanisms.

Bushing 210 abuts locking member 204 and has a sleeve portion that has the same or smaller outer diameter than the supported locking member 204. Ratchet ring 135 abuts bushing 210 and stroke limiter 180 abuts ratchet ring 135 (FIG. 2). With locking member 204 locked out, bushing 210, ratchet ring 135 and stroke limiter 180 are prevented from shifting in the first direction when indexing piston 110 pushes against stroke limiter 180.

After a predetermined number of indexes, indexing mechanism 103 can be in an activation configuration such that the next cycle that actuates indexing piston 110 causes ratchet 150 to push indexing member 112 onto activation pin 114 and push activation pin 114 in the first direction. A releasable locking mechanism, such as shear pins 223, a c-ring or other locking mechanism can be provided such that the holding force of the releasable locking mechanism must be overcome for activation pin 114 to move relative to locking members 204. In some cases, this means that the activation pressure required for indexing mechanism 103 to activate a tool may be higher than the indexing pressure.

When sufficient force is asserted on activation pin 114 to overcome the holding force, activation pin 114 can shift in the first direction. As activation pin 114 shifts in the first direction, projections 222 come into alignment with recesses 220 and allow locking member 204 to radially collapse so that locking member 204 can shift with activation pin 114. Activation pin 114 can shift to unseal inner bore 104 at unloader module 202.

Locking member 204 can unlock to provide a piston release configuration that allows piston 110 to shift to unseal piston seal 118 (see, FIG. 12). As shown in FIG. 5, when locking member 204 unlocks and shifts, a portion of bushing 210 can slide axially into unloader module 202. Consequently, indexing piston 110 can push a stack of components, including stroke limiter 180, ratchet ring 135 and bushing 210 in the first direction. A flange portion or other portion of bushing 210 can come to rest against a stop to prevent movement of the stack greater than a predefined distance.

Movement of activation pin 114 may be limited. In the embodiment illustrated, activation pin 114 shifts until a projection 222 bottoms out against a stop formed by a shoulder of unloader module 202. In another embodiment, activation pin 114 may shift until locking member 204 abuts the stop. One of ordinary skill in the art would understand that other suitable mechanisms to prevent further movement of activation pin 114 may also be used.

Because stroke limiter 180 can shift in the first direction, indexing piston 110 can actuate further in the activation cycle than in prior indexing cycles. According to one embodiment indexing piston 110 can actuate during the activation cycle a sufficient distance such that piston seal 118 can enter an area of larger diameter, breaking the seal. With the seals initially formed by piston seal 118 and seal 203 broken inner bore 104 is no longer sealed and a flow path can be established through indexing mechanism 103. The various components of indexing mechanism 103 can be formed such that a flow passage is created from first end 106 a to second end 106 b of the indexing mechanism inner bore 104. Accordingly, the indexing device 100 can connect a higher pressure/lower pressure source fluidly connected to the first end 106 a to an area of a tool connected to second end 106 b or vice versa to activate the tool.

With reference to FIGS. 6-8, another embodiment of an activation mechanism 300 is illustrated. According to one embodiment, activation mechanism comprises a unloader module 302 having a rupture disk 315 (or other activation mechanism seal) disposed to seal inner bore 104, activation pin 314 and one or more locking members 304. Activation mechanism 300 operates similarly to activation mechanism 200 except that unloader module 302 includes a rupture disk 315 or other seal that activation pin 314 punctures. In the embodiment illustrated, indexing member 112 pushes on activation pin 314 such that activation pin 314 pierces rupture disk 315, thereby connecting the indexing mechanism inner bore with an area of a tool. Movement of activation pin 314 may be limited. In the embodiment illustrated, activation pin 314 shifts until a projection 322 bottoms out against a stop formed by a shoulder of unloader module 302. In another embodiment, activation pin 314 may shift until locking member 304 abuts the stop. One of ordinary skill in the art would understand that other suitable mechanisms to prevent further movement of activation pin 314 may also be used. FIGS. 6-8 further illustrate shifting of bushing 210, ratchet ring 135 and stroke limiter 180 as discussed above.

Turning briefly to FIGS. 9-12, FIGS. 9-12 are diagrammatic representations of one embodiment of a portion of indexing mechanism 103 proximate to end 106 a illustrated in more detail. In the embodiment illustrated, indexing mechanism 103 includes a first end tubular 128 that provides fluidic connection between inner bore 104 and tubing pressure (or other applied pressure). In some cases, it may be desirable to isolate indexing piston 110 from tubing pressure during installation in a wellbore. Accordingly, a rupture disk 130 can be provided. At run-in, piston face 120 may be disposed in an area of atmospheric pressure 132 (or other selected pressure). When the tubing pressure exceeds a rupture pressure, the rupture disk 130 can rupture, exposing piston face 120 to tubing pressure.

A piston head seal tubular 134 can help seal one side of indexing piston 110 from the other so that a pressure differential can be established across seal 118. A static seal 133 disposed between the outer surface of piston head seal tubular 134 and housing 101 helps inhibit leaks of potentially high pressure fluid along the inner surfaces of housing 101 into the reference pressure chamber 122. Piston head seal tubular 134 further provides a piston seal bore having a piston seal surface 119 with which piston seal 118 can maintain a seal throughout its range of motion during indexing cycles.

FIGS. 10 and 11 illustrate an example of piston seal 118's range of motion when indexing mechanism 103 is in an indexing configuration. As indexing piston 110 actuates in the first direction during indexing cycles, piston seal 118 maintains a seal between indexing piston 110 and the inner surface of bore 104 at piston seal surface 119 throughout its range of motion. FIG. 10 illustrates piston seal 118 between piston head portion 115 and seal surface 119 in an initial position (non-actuated) and FIG. 11 illustrates piston seal 118 when indexing piston 110 has overcome spring 124 and moved to a second position corresponding to the end of its indexing stroke in the first direction.

As discussed above, during an activation cycle, indexing piston 110 can actuate further than in prior indexing cycles. According to one embodiment, indexing piston 110 can actuate during the activation cycle a sufficient distance such that piston seal 118 can enter an area of larger diameter, breaking the seal as shown, for example, in FIG. 12. Piston 110 can include an area smaller outer diameter 121 proximate to piston face 120 having a sufficient length such that a flow passage is formed between the area of smaller diameter 121 and sealing surface 119 when piston seal 118 travels out of the piston seal bore, thereby allowing fluid flow into/out of chamber 122.

FIGS. 25A and 25B (collectively FIG. 25) are diagrammatic representations illustrating another embodiment of portion of an indexing mechanism proximate to end 106 a. In the embodiment of FIGS. 25A and 25B, the indexing piston includes a piston head portion 1515 that includes extendable segments 1550 that prevent the piston seal 1518 from resealing in the piston seal bore after the indexing piston is released.

In the embodiment of FIGS. 25A and 25B, the indexing mechanism includes a first end tubular 1528 that provides fluidic connection between the indexing device inner bore and tubing pressure (or other applied pressure). In some cases, it may be desirable to isolate the indexing piston from tubing pressure during installation in a wellbore. Accordingly, a rupture disk 1530 can be provided. At run-in, piston face 1520 may be disposed in an area of atmospheric pressure 1532 (or other selected pressure). When the tubing pressure exceeds a rupture pressure, the rupture disk 1530 can rupture, exposing piston face 1520 to tubing pressure.

A piston head seal tubular 1534 can help seal one side of the indexing piston from the other so that a pressure differential can be established across seal 1518. A static seal 1533 disposed between the outer surface of piston head seal tubular 1534 and housing 101 helps inhibit leaks of potentially high pressure fluid along the inner surfaces of housing 101 into a reference pressure chamber. Piston head seal tubular 1534 further provides a piston seal bore having a piston seal surface 1519 with which piston seal 1518 can maintain a seal throughout its range of motion during indexing cycles.

In the embodiment of FIGS. 25A-25B, piston head portion 1515 includes an extendable locking mechanism that can be released to prevent the indexing piston from resealing with the piston seal bore. Extendable segments 1550 comprise spring loaded or otherwise extendable plates, dogs, detents or other structures. In one embodiment, extendable segments may be provided by a c-ring. In a collapsed configuration (FIG. 25A), extendable segments 1550 have a first effective outer diameter and, in an extended configuration (FIG. 25B), extendable segments have a second effective outer diameter greater than the first effective outer diameter.

When the indexing mechanism is in an indexing configuration, piston seal 1518 remains in the piston seal bore throughout its range of motion and extendable segments 1550 at least partially remain in a portion of the inner bore (portion 1552) having an inner diameter that retains extendable segments 1550 in the collapsed configuration. However, as illustrated in FIG. 25B, when the indexing mechanism is in a piston release configuration (for example, when an activation mechanism 200, 300 releases), piston seal 1518 can travel into an area of larger diameter such that the seal between piston seal 1518 and piston seal surface 1519 is broken. The indexing piston can include an area smaller outer diameter 1521 proximate to piston face 1520 having a sufficient length such that a flow passage is formed between the area of smaller diameter 1521 and sealing surface 1519 when piston seal 1518 travels out of the piston seal bore, thereby allowing fluid flow into/out of chamber 1522. Furthermore, extendable segments 1550 can travel over a stop 1554 into an area of a larger inner diameter (indicated at 1556) that allows extendable segments 1550 to extend. Interference between extendable segments 1550 in the extended configuration and stop 1554 can prevent piston seal 1518 from reentering the piston seal bore.

Embodiments described herein allow a hydraulically activated tool to be pressure tested for multiple cycles without activating the tool. After the tool has been pressure tested, the tool can be activated at a potentially lower pressure. In addition to providing pressure test capability, indexing mechanisms described herein contribute to high pressure capability. The indexing mechanisms can be installed in relatively small diameter holes such that any atmospheric chambers used in the indexing mechanism may be small diameter, high pressure atmospheric chambers. A tool incorporating indexing mechanisms described herein may have a higher pressure rating for a similar size due to the smaller atmospheric chamber. Moreover, the indexing mechanisms can be relatively small and multiple indexing mechanisms can be used in parallel and/or in series, creating redundancy and flexibility.

Indexing mechanisms described herein can be coupled to or incorporated into a variety of tools. Indexing mechanisms can be incorporated in an integral way into tools or can be incorporated by a separate connection by means of a control line, electrical cable or other connection. One example of a wellbore tool that can incorporate an indexing mechanism is a hydraulically activated ported tool, such a toe port tool (sometimes referred to as a “toe sleeve”). In one embodiment of a hydraulically activated ported tool, an indexing mechanism can be operatively coupled to a sliding sleeve. Upon a preset number of pressure cycles of at least an indexing pressure, the indexing mechanism can open one side of the sliding sleeve to higher or lower pressure to move the sleeve to a port open position. Through the use of the indexing mechanism, the hydraulically activated ported tool can be pressure tested multiple times at or above the tool's activation pressure prior to opening.

FIG. 13 is a diagrammatic representation of a cross-sectional view of one embodiment of a pressure testable hydraulically activated ported tool 410. The purpose of ported tool 410 may depend on its position in the well. For example, the tool may be useful as a toe port tool installed adjacent the distal end, or toe, of a tubing string. The toe port tool may be used to create fluid conductivity to the annulus and/or for fluid treatment. If tool 410 is positioned closer to surface it may be considered a fluid treatment tool. Tool 410 may be employed, for example, alone or in series with other tools along the length of the tubing string.

Ported tool 410 includes an opening assembly 430 with ports 412 that can be opened by shifting sleeve 420 to provide fluid access between the tubing string inner bore 416 and the annular area between the tubing string and wellbore wall. Tool 410 includes an indexing assembly 440 with an indexing mechanism 442 that can be configured to activate tool 410 to open ports 412. Indexing mechanism 442, however, can allow multiple pressure tests of tool 410 at higher pressures than are needed to activate sleeve 420.

Ported tool 410 has a tubular housing having first end 414 a, a second end 414 b, an inner surface 414 c and an outer surface 414 d. Inner surface 414 c defines an inner bore 416 that extends from first end 414 a to second end 414 b. Although not shown, ported tool 410 may be formed as a sub having ends threaded or otherwise formed such that ported tool 410 may be connected into a wellbore tubular string.

Opening assembly 430 includes ports 412 through a housing wall that, when open, provides fluid access from the inner bore 416 to the outer surface 414d. Sleeve 420 acts as a closure to control the open and closed condition of ports 412. Sleeve 420 moves axially from a port closed position, wherein sleeve 420 blocks and closes ports 412, to a port open position, wherein sleeve 420 leaves ports 412 at least partially open such that there is fluid communication between the inner bore 416 to the outer surface 414 d.

With reference to FIGS. 13-15, the tool housing includes an outer ported housing 432 and inner mandrel 434 arranged to form an annular space 436 between the inner surface of ported housing 432 and the outer surface of mandrel 434, and between the annular space's first end wall 436 a and the annular space's second end wall 436 b. In the embodiment illustrated, ported housing 432 and mandrel 434 extend between a first tubular connector 438 and a second tubular connection 439 to form annular space 436. Sleeve 420 is axially slidable in annular space 436 along the outer surface of mandrel 434 from a port closed position (FIG. 14) to a port open position (FIG. 15). Ported housing 432, mandrel 434 and sleeve 420 may include one or more seals to prevent fluid flow between mandrel 434 and sleeve 420 and between sleeve 420 and ported housing 432 when sleeve 420 is in the closed position.

Ported housing 432, mandrel 434 and sleeve 420 may each include at least one aperture (e.g., ports 412, ports 444 and ports 446, respectively) positioned such that fluid communication between bore 416 and the surrounding wellbore is established when sleeve 420 slides to the port open position (FIG. 15). One or more alignment mechanisms may be used to help ensure that ports 444 remain rotationally aligned with ports 412 and 446. For example, sleeve 420 may include one or more alignment pins 447 that ride in axial slots 449 on the outer surface of mandrel 434 to prevent relative rotation of sleeve 420. In another embodiment, sleeve 420 does not include ports 446, but is sized such that sleeve 420 will not block ports 412 when in the port open position. When in the port closed position, sleeve 420 covers ports 412 and/or ports 444 to prevent fluid flow.

Sleeve 420 includes first piston face 448a exposed to a first pressure chamber 450 and a second piston face 448 b exposed to a second pressure chamber 452. First pressure chamber 450 may be an upper pressure chamber and second pressure chamber 452 may be a lower pressure chamber, or vice versa. Sleeve 420 can be opened by controlling the pressure in pressure chamber 450 or pressure chamber 452. First pressure chamber 450 and second pressure chamber 452 may be hydraulic pressure chambers containing a hydraulic fluid such as oil (e.g., silicone oil or other oil) or other hydraulic fluid. The use of oil filled chambers can provide several advantages. Because liquid is less compressible than gas, the liquid filled chamber will better prevent the walls from deforming compared to an atmospheric chamber. Moreover, liquid filled chambers allow the for pressure compensation in a much smaller volume than atmospheric chambers.

A pressure compensation piston 460 having piston faces 462 a and 462 b is disposed in annular space 436 and is axially slidable along the outer surface of mandrel 434. Ported housing 432, mandrel 434 and compensation piston 460 may include one or more seals to prevent leaks across compensation piston 460. Piston face 462 a is exposed to pressure in second pressure chamber 452 whereas piston face 462 b is exposed to pressure in area 463 of annular space 436. A flow path 464 is provided such that piston face 462 b is exposed to tubing pressure. In one embodiment, flow path 464 is formed by a gap between mandrel 434 and second tubular connection 439. However, the flow path may be formed in any suitable manner including, but not limited to, a port through mandrel 434 that connects the inner bore 416 to area 463. A rupture disk or other mechanism can be provided in some embodiments such that piston face 462 b is not exposed to tubing pressure until the tubing pressure reaches a predetermined pressure.

Compensation piston 460 may be configured, in one embodiment, to equalize the pressure in second pressure chamber 452 with the tubing pressure. In such an embodiment, compensation piston 460 can increase the pressure in second pressure chamber 452 as the tubing pressure increases. In turn, sleeve 420 can increase pressure in first pressure chamber 450 until the forces on sleeve 420 are balanced. In addition to responding to tubing pressure changes, compensation piston 460 and sleeve 420 may move to compensate for thermal expansion in second pressure chamber 452 and first pressure chamber 450.

In another embodiment, piston face 448 b may be exposed directly to fluid from the tubing string. For example, compensation piston 460 may be omitted. However, the use of an oil filled chamber 452 can enhance performance of the tool. Hydraulic oil (e.g., silicone oil or other oil) can prevent well debris from causing friction or corrosion of the sleeve 420.

A biasing member may be provided to bias sleeve 420 to an open or closed position. In the embodiment illustrated in FIG. 13, for example, a compression spring 466 in second pressure chambers 452 is compressed between sleeve 420 and a snap ring assembly 470. In another embodiment, compression spring 466 may be compressed between compensation piston 460 and sleeve 420. Spring 466 asserts force on movable sleeve 420 to bias movable sleeve 420 to an open position. Sleeve 420 will increase the pressure in first pressure chamber 450 until the pressure in first pressure chamber 450 balances the forces asserted on sleeve 420 by the pressure in second pressure chamber 452 and spring 466. In one embodiment, tool 410 can be configured such that the pressure in first pressure chamber 450 is approximately equal to the tubing pressure plus a spring pressure (pressure required to balance the spring force of spring 466).

Maintaining chambers 450 and 452 at or near the tubing pressure can provide for a smoother and less violent opening than conventional tools. As will be discussed in more detail below, indexing mechanism 442 can be configured to vent first pressure chamber 450 such that sleeve 420 can move to a port open position (shown in FIG. 15). In one embodiment, indexing mechanism 442 opens a flow path between first pressure chamber 450 and the inner bore 416. As the pressure in first pressure chamber 450 drops to the tubing pressure, spring 466 can shift sleeve 420 to an open position and compensation piston 460 can shift to compensate for movement of sleeve 420. In this embodiment, the sleeve is moved by the spring force rather than a pressure differential.

Maintaining chambers 450 and 452 at or near the tubing pressure means that the pressure differential across the inner and/or outer walls adjacent to the pressure compensated chambers 450 and 452 will be relatively small when compared to atmospheric chambers, particularly as the tubing pressure increases. Consequently, a tool 410 that is configured to maintain chambers 450 and 452 at or near the tubing pressure is less likely to deform and jam.

It can be noted that sleeve 420 and compensation piston 460 may be unrestrained by shear pins or other locking mechanisms that prevent axial movement and may be free to slide in annular space 436 to achieve force balanced states even during installation. In other embodiments, shear pins or other releasable locking mechanisms may be provided such that a threshold pressure differential must be obtained across piston 460 to overcome a holding force before piston 460 moves from its run in position and/or such that a threshold pressure differential must be obtained across sleeve 420 to overcome a holding force before sleeve 420 moves from its run in position.

As discussed above, an indexing assembly 440 can be provided that allows tool 410 to be pressure tested multiple times at pressures greater than the pressure required to activate tool 410. With reference to FIG. 13, one embodiment of indexing assembly 440 can comprise a housing 480 that houses one or more indexing mechanisms 442. Indexing mechanism 442 may include indexing mechanisms such as described in conjunction with FIGS. 1-12, other indexing mechanisms discussed herein or other indexing mechanism. Housing 480 may be formed as a tubular that can be coupled to other subs in a string. The indexing mechanism 442 can be configured such that tool 410 can be tested over a number of pressure cycles that meet or exceed the indexing pressure (assuming the pressure does not otherwise exceed operational limits of the tool). If, after pressure testing, there are remaining indexing cycles, the pressure can be cycled to complete the remaining indexing cycles and activate the tool. On the last cycle, the indexing mechanism can operate to cause sleeve 420 to move to a port open position. The pressure cycles used to complete the remaining indexing cycles and activate tool 410 can be done at the indexing pressure or activation pressure (if different than the indexing pressure), which may be lower than the pressure test pressure.

According to one embodiment, an indexing mechanism 442 can be actuated by tubing pressure. Using the example of indexing device 100 of FIG. 1, a first end 106 a may be exposed to tubing pressure through a flow passage between housing 480 and sub 491 that connects first end 106 a to inner bore 416. Second end 106 b may be connected to first pressure chamber 450 as shown, for example, in FIG. 16. Pressure may be cycled in the tubing string to at least the indexing pressure to actuate indexing piston 110 and advance indexing member 112. After a predetermined number of cycles, activation mechanism 200, 300 can activate to unseal second end 106 b and create a flow passage through the indexing mechanism. This will open first chamber 450 to tubing pressure allowing first chamber 450 to vent. As a result, spring 466 can push sleeve 420 to the open position.

Thus, tool 410 has a first tool configuration (a pre-activation configuration) in which the first side of sleeve 420 is exposed to a pressure chamber 450 that is isolated from tubing bore 416 and a second tool configuration (an activated configuration) in which pressure chamber 450 is fluidly connected to bore 416. In this embodiment, the indexing mechanism prevents sleeve 420 from activating for a predetermined number of indexes by keeping first pressure chamber 450 isolated from inner bore 416. After the predetermined number of indexes, the indexing mechanism activates sleeve 420 by exposing chamber 450 to bore 416.

FIG. 16 illustrates one embodiment of indexing assembly 440 coupled to opening assembly 430 by tubular connector 438. According to one embodiment, tubular connector 438 defines a flow passage 495 from an inner bore indexing mechanism 442 (e.g., inner bore 104 of indexing mechanism 103 or other indexing mechanism) to first pressure chamber 450. In the embodiment illustrated, the flow passage 495 is defined by machined flow passage 497 and a gap 498 between an inner surface of tubular connector 438 and an outer surface of mandrel 434. The flow passage 495, however, can be otherwise configured to connect first pressure chamber 450 with the inner bore of the indexing mechanism 442.

Indexing mechanism 442 can unseal the indexing mechanism's inner bore to create a flow passage from first pressure chamber 450 to the inner bore 416 of tool 410. Accordingly, first pressure chamber 450 can vent such that spring 466 can shift sleeve 420 to the port open position as shown in FIG. 15. As discussed above, this opening process can be relatively gentle because only the spring force is required to move sleeve 420.

FIG. 17 is a diagrammatic representation of one embodiment of a ported tool 500 in which an opening assembly 530 is coupled to an indexing assembly 540 by tubular connection 538. Opening assembly 530 can be similar to opening assembly 430 and indexing assembly 540 may be similar to indexing assembly 440 except that indexing assembly 540 includes multiple indexing mechanisms 542 operatively coupled to pressure chamber 550. The indexing mechanisms may be configured to have approximately the same indexing pressure. If a single indexing mechanism 542 fails, the other may continue to operate. Any number of indexing mechanisms 542 can be used in parallel.

While discussed primarily in the context of use with a toe port tool, the indexing mechanisms discussed above may be used with a variety of tools including, but not limited to, well treatment tools, packers, perforators or other tools. Furthermore, while the indexing mechanisms of FIGS. 1-17, 25 have been described primarily in terms of venting pressure from a portion of a tool, indexing mechanisms described herein may be used to increase pressure. For example, an indexing mechanism can be configured to connect tubing pressure to an atmospheric chamber to activate a tool.

FIGS. 18-23 are diagrammatic representations of various additional embodiments of indexing devices that can be used to provide a pressure testable tool. The indexing mechanisms illustrated include a ratcheting device that moves (indexes) a limited distance relative to other parts in response to pressure (or other energy source) applied to the indexing mechanism. The indexing mechanism can be configured to pressure cycles reaching a threshold indexing pressure, but not index further as pressure is increased above the indexing pressure. A tool can be pressure tested multiple times at pressures above the indexing pressure without being activated. After a preset number of indexes, an indexing mechanism can be responsive to the next pressure cycle to the indexing pressure or above (or other trigger event) to cause a targeted wellbore tool to be activated.

With reference to FIG. 18, one embodiment of an indexing device 600 that allows a tool to be pressure tested multiple times at pressures greater than the pressure required to activate the tool is illustrated. According to one embodiment, indexing device 600 includes a housing 601 that houses an indexing mechanism 603. Housing 601, in cooperation with components of indexing mechanism 603, define inner surfaces of an indexing mechanism inner bore 604 that extends from a first end 606 a to a second end 606 b. Housing 601 can take various forms. According to one embodiment, housing 601 may comprise the walls of a sub or other tool in which an indexing mechanism 603 is installed. In other embodiments, indexing device 600 may be formed as a cartridge with an independent housing, such that indexing device 600 with housing 601 can be installed in an opening in a tool.

Indexing mechanism 603 further includes a reciprocating piston 630 that reciprocates in inner bore 604. By relative movement of between piston 630 and housing 601, piston 630 can advance indexing member 636 in a first direction and push indexing member 636 against an activation pin 640. According to one embodiment, piston 630 can advance indexing member 636 a predefined amount to a new indexing position each time piston 630 actuates sufficiently in the first direction. Thus, piston can be actuated a number of times before it pushes indexing member 636 against activating pin 640 to shift activating pin 640. Activating pin 640 may shift through end sub 687 to puncture a rupture disk, remove a plug, trigger an electronic component, detonate a charge or otherwise cause a tool to change state such that the tool activates.

In one embodiment, piston 630 actuates responsive to pressure cycles that reach at least an indexing pressure. If the pressure asserted on piston 630 (e.g., the tubing pressure or other pressure) increases to at least an indexing pressure, piston 630 actuates in a first direction to move indexing member 636 to a new indexing position, but does not return indexing member 636 to the previous indexing position on the return stroke. Through multiple pressure cycles at or above the indexing pressure, indexing member 636 can be moved incrementally in the first direction. After a preset number of indexes, indexing mechanism 603 changes from an indexing configuration to an activation configuration. On the next pressure cycle above the indexing pressure, indexing member pushes activating pin 640 to activate the tool.

Indexing mechanism 603 can be configured such that the pressure asserted on piston 630 in a cycle may exceed the indexing pressure without over indexing. Consequently, a tool can be pressure tested multiple times at pressures above the indexing pressure without being activated. After pressure testing, pressure cycles can be used to complete any remaining indexing cycles and activate the tool.

Piston 630 may include a first piston face 662. By creating a differential across seal 663, piston 630 may actuate in the first direction. According to one embodiment, second piston face 664 is exposed to an atmospheric chamber 667 (or other reference pressure) and piston face 662 is exposed to tubing pressure (or other pressure source) to create a pressure differential across piston 630. A biasing member may bias piston 630 in the second direction such that the pressure asserted on face 662 must reach a threshold indexing pressure for piston 630 to actuate a sufficient distance to index indexing member 636. In the embodiment depicted, a compression spring 670 (e.g., a Bellville spring or other suitable spring) is provided in atmospheric chamber 667 that biases piston 630 to a starting or non-actuated position.

A hydrostatic preloader 624 can be provided to compensate for anticipated hydrostatic pressure such that a threshold amount of applied pressure is required in the tubing string to actuate piston 630 and index indexing member 636. Hydrostatic preloader 624 can set the initial compression in spring 670 such that piston 630 will not actuate due to anticipated hydrostatic pressure but will instead require a threshold pressure above hydrostatic to actuate. In the embodiment illustrated, hydrostatic preloader 624 comprises a tubular that can be threaded into outer housing 601 to a selected depth to push on shoulder 683 of piston 630 and compress spring 670 a desired amount to preload spring 670. Other mechanisms can also be used to preload spring 670.

Piston 630 includes a ratchet 632 that has an indexing profile 634 defined on its outer surface. Ratchet 632 can reciprocate in a ratchet portion of inner bore 604 that includes an indexing profile 628 defined on an inner wall surface of inner bore 604. According to one embodiment, the ratchet portion may be provided by a ratchet ring 642. Indexing member 636 is disposed between ratchet 632 and the inner wall surface of inner bore 604. Indexing member 636, according to one embodiment, comprises a flexible c-ring, lock ring or other structure that has an outer surface facing the inner wall surface of bore 604 and an inner surface facing ratchet 632. The outer surface of indexing member 636 includes an indexing profile 638 to selectively engage indexing profile 628 and the inner surface of indexing member 636 includes an indexing profile 639 to selectively engage indexing profile 634. The indexing profiles 628, 638, 634, 639 can be configured so that indexing member 636 moves with ratchet 632 when ratchet 632 moves in the first direction, but does not move to its previous position when ratchet 632 moves in the second direction. Consequently, by relative movement of between piston 630 and housing 601, indexing member 636 moves incrementally in a first direction with each stroke of ratchet 632 in the first direction but does not move back with ratchet 632 on the return stroke. According to one embodiment, the ratchet mechanism may operate similarly to the manner described in conjunction with FIGS. 5-6 above.

A stroke limiter 680 is provided to limit the stroke of piston 630 to a known distance. Consequently, indexing member 636 can move a known amount even if the pressure asserted on piston 630 substantially exceeds the indexing pressure. Stroke limiter 680 thus prevents over indexing when the pressure on piston 630 exceeds the indexing pressure. Accordingly, pressure tests can occur at pressures higher than the indexing pressure without prematurely activating the tool.

According to one embodiment, stroke limiter 680 comprises a shoulder 682 spaced from a facing shoulder 684 and positioned to abut facing shoulder 684 when piston 630 has moved a desired distance in the first direction. According to one embodiment, stroke limiter 680 is configured so that indexing member 636 moves between indexing positions that are a single tooth length “L” apart for a predetermined number of cycles. Stroke limiter 680 can be configured, for example, so that the ratchet 632 moves at least the length “L” of the teeth and less than 2 “L”. In accordance with one embodiment, stroke limiter 680 can limit the stroke of ratchet 632 to 1.3-1.5 “L”. In other embodiments, the stroke limiter 680 can allow the stroke to be greater than 2 L, but such an embodiment would reduce the number of indexing positions for the same number of teeth and may result in partial indexing.

FIG. 19 is a diagrammatic representation of another embodiment of an indexing device 700. Indexing device 700 includes a tubular housing 702 housing an indexing mechanism 710. Indexing mechanism 710 may include an indexing mechanism inner bore 714 that has a first end 716 a connected to the inner bore of a sub by a flow passage 706. The second end 716 b of inner bore 714 may be connect to another pressure area 708, such as the annulus surrounding a tubing string, another tool, a pressure chamber or other pressure area.

Indexing mechanism 710 further includes a reciprocating piston 730 that reciprocates in inner bore 714. By relative movement of between piston 730 and housing 702, piston 730 can advance indexing member 736 in a first direction and push indexing member 736 against an activation pin 740. According to one embodiment, piston 730 can advance indexing member 736 a predefined amount to a new indexing position each time piston 730 actuates sufficiently in the first direction. After a number of movements (cycles of piston 730), piston 730 can push indexing member 736 against activating pin 740 to shift activating pin 740. Activating pin 740 may shift through end sub 787 to puncture a rupture disk, remove a plug, trigger an electronic component, detonate a charge or otherwise cause a tool to change state such that the tool activates.

In one embodiment, piston 730 actuates responsive to hydraulic or mechanical pressure. Piston 730 can be responsive to pressure cycles of at least an indexing pressure to actuate in a first direction to move indexing member 736 to a new indexing position. Piston 730, however, does not return indexing member 736 to the previous indexing position on the return stroke. Through multiple pressure cycles at or above the indexing pressure, indexing member 736 can be incrementally moved in the first direction until it pushes activating pin 740 to activate the tool. Indexing mechanism 710 can be configured such that the pressure asserted on piston 730 in a cycle may exceed the indexing pressure without over indexing. Consequently, a tool can be pressure tested multiple times at pressures above the indexing pressure without being activated. After pressure testing, pressure cycles can be used to complete any remaining indexing cycles to activate the tool.

Piston 730 may include a first piston face 762 and a second piston face 764. By creating a differential across piston seal 763, piston 730 may actuate in the first direction. According to one embodiment, second piston face 764 is exposed to an atmospheric chamber 766 (or other reference pressure) and piston face 762 is exposed to tubing pressure (or other pressure source) to create a pressure differential across piston 730. According to one embodiment, however, a rupture disk 733 or other mechanism may isolate piston face 762 from tubing pressure until the tubing pressure reaches a predetermined threshold.

A biasing member may bias piston 730 in the second direction such that the pressure on piston face 762 must reach a threshold indexing pressure for piston 730 to actuate a sufficient distance to index indexing member 736. In the embodiment depicted, a compression spring 770 (e.g., a Bellville spring or other suitable spring) is provided in atmospheric chamber 766 that biases piston 730 to a starting or non-actuated position.

A hydrostatic preloader 724 can be provided to compensate for anticipated hydrostatic pressure such that a threshold amount of applied pressure is required in the tubing string to actuate piston 730 and index indexing member 736. In the embodiment illustrated, hydrostatic preloader 724 comprises a connection (e.g., a threaded connection) between portions of piston shaft 731 such that the length of piston 730 can be adjusted. By adjusting the length of piston 730 the preload in spring 770 can be set. Other hydrostatic freeloaders may also be used.

Piston 730 includes a ratchet 732 that has an indexing profile 734 defined on its outer surface. Ratchet 732 can reciprocate in a ratchet portion of inner bore 714 that includes an indexing profile 728 defined on an inner wall surface of inner bore 714. According to one embodiment, the ratchet portion may be defined by a ratchet ring 742. Indexing member 736 is disposed between ratchet 732 and the inner wall surface of ratchet ring 742. Indexing member 736, according to one embodiment, comprises a flexible c-ring, lock ring or other structure that has an outer surface facing the inner wall surface of bore 714 and an inner surface facing ratchet 732. The outer surface of indexing member 736 includes an indexing profile 738 to selectively engage indexing profile 728 and the inner surface of indexing member 736 includes an indexing profile 739 to selectively engage indexing profile 734. The indexing profiles 728, 738, 734, 739 can be configured so that indexing member 736 moves with ratchet 732 when ratchet 732 moves in the first direction, but does not move to its previous position when ratchet 732 moves in the second direction. Consequently, by relative movement of between piston 730 and ratchet ring 742, indexing member 736 moves incrementally in a first direction with each stroke of ratchet 732 in the first direction but does not move back with ratchet 732 on the return stroke. According to one embodiment, the ratchet mechanism may operate similarly to the manner described in conjunction with FIGS. 5-6 above.

A stroke limiter 780 is provided to limit the stroke of piston 730 to a known distance. Consequently, indexing member 736 can move a known amount even if the pressure asserted on piston 730 substantially exceeds the indexing pressure. Stroke limiter 780 thus prevents over indexing when the pressure on piston 730 exceeds the indexing pressure. Accordingly, pressure tests can occur at pressures higher than the indexing pressure without prematurely activating the tool.

According to one embodiment, stroke limiter 780 comprises a tubular having a shoulder 782 spaced from a facing shoulder 784 of piston 730 and positioned to abut facing shoulder 784 when piston 730 has moved a desired distance in the first direction. According to one embodiment, stroke limiter 780 is configured so that indexing member 736 moves between indexing positions that are a single tooth length “L” apart for a predetermined number of cycles. Stroke limiter 780 can be configured, for example, so that the ratchet 732 moves at least the length “L” of the teeth and less than 2 “L”. In accordance with one embodiment, stroke limiter 780 can limit the stroke of ratchet 632 to 1.3-1.5 “L”. In other embodiments, the stroke limiter 780 can allow the stroke to be greater than 2 “L”, but such an embodiment would reduce the number of indexing positions for the same number of teeth and result in partial indexing.

FIG. 20 is a diagrammatic representation of another embodiment of an indexing device 800. Indexing device 800 includes a tubular housing 802 housing an indexing mechanism 810. Indexing mechanism 810 may include an indexing mechanism inner bore 814 that has a first end 816 a connected to the inner bore of a sub by a flow passage 806. The second end 816 b of inner bore 814 may connect to another pressure area 808, such as the annulus surrounding a tubing string, another tool, a pressure chamber or other pressure area.

Indexing mechanism 810 further includes a reciprocating piston 830 that reciprocates in inner bore 814. By relative movement of between piston 830 and housing 802, piston 830 can advance indexing member 836 in a first direction and push indexing member 836 against an activation pin 840. According to one embodiment, piston 830 can advance indexing member 836 a predefined amount to a new indexing position each time piston 830 actuates sufficiently in the first direction. After a number of movements, piston 830 can push indexing member 836 against activating pin 840 to shift activating pin 840.

In one embodiment, piston 830 actuates responsive to hydraulic or mechanical pressure. Piston 830 can be responsive to pressure cycles of at least an indexing pressure to move indexing member 836 to a new indexing position. Piston 830, however, does not return indexing member 836 to the previous indexing position on the return stroke. Through multiple pressure cycles at or above the indexing pressure, indexing member 836 can be moved in the first direction until it pushes activating pin 840 to activate the tool. Indexing mechanism 810 can be configured such that the pressure asserted on piston 830 in a cycle may exceed the indexing pressure without over indexing. Consequently, a tool can be pressure tested multiple times at pressures above the indexing pressure without being activated. After pressure testing, pressure cycles can be used to complete any remaining indexing cycles to activate the tool.

Piston 830 may include a first piston face 862 and a second piston face 864. By creating a differential pressure across piston seal 833, piston 830 may actuate in the first direction. According to one embodiment, second piston face 864 is exposed to an atmospheric chamber 866 (or other reference pressure) and piston face 862 is exposed to tubing pressure (or other pressure source) to create a pressure differential across piston 830. According to one embodiment, however, a rupture disk or other mechanism may isolate piston face 862 from tubing pressure until the tubing pressure reaches a predetermined threshold.

A biasing member may bias piston 830 in the second direction such that the pressure on piston face 862 must reach a threshold to actuate piston 830 a sufficient distance to index indexing member 836. In the embodiment depicted, a compression spring 870 (e.g., a Bellville spring or other suitable spring) is provided in atmospheric chamber 866 that biases piston 830 to a starting or non-actuated position.

Piston face 862 may be exposed to hydrostatic pressure (e.g., hydrostatic pressure in a tubing string) that will naturally result in a pressure differential between piston face 862 and piston face 864. The hydrostatic pressure will depend on the location of indexing mechanism 810 in the tubing string. Indexing mechanism 810, however, can be configured so that at least some minimum pressure above hydrostatic is required to index. A hydrostatic preloader 824 can be provided to compensate for anticipated hydrostatic pressure such that a threshold amount of applied pressure is required in the tubing string to actuate piston 830 and index indexing member 836.

Hydrostatic preloader 824 can set the initial compression in spring 870 such that piston 830 will not actuate due to anticipated hydrostatic pressure but will instead require a threshold pressure above hydrostatic to actuate. In the embodiment illustrated, hydrostatic preloader 824 comprises a connection (e.g., a threaded connection) between portions of piston shaft 831 such that the length of piston 830 can be adjusted. Other hydrostatic freeloaders may also be used.

Piston 830 includes a ratchet 832 that has an indexing profile 834 defined on its outer surface. Ratchet 832 can reciprocate in a ratchet portion of inner bore 814 that includes an indexing profile 828 defined on an inner wall surface of inner bore 814. According to one embodiment, the ratchet portion may be defined by a ratchet ring 842. Indexing member 836 is disposed between ratchet 832 and the inner wall surface of ratchet ring 842. Indexing member 836, according to one embodiment, comprises a flexible c-ring, lock ring or other structure that has an outer surface facing the inner wall surface of bore 814 and an inner surface facing ratchet 832. The outer surface of indexing member 836 includes an indexing profile 838 to selectively engage indexing profile 828 and the inner surface of indexing member 836 includes an indexing profile 839 to selectively engage indexing profile 834. The indexing profiles 828, 838, 834, 839 can be configured so that indexing member 836 moves with ratchet 832 when ratchet 832 moves in the first direction, but does not move to its previous position when ratchet 832 moves in the second direction. Consequently, by relative movement of between piston 830 and ratchet ring 842, indexing member 836 moves incrementally in a first direction with each stroke of ratchet 832 in the first direction but does not move back with ratchet 832 on the return stroke. According to one embodiment, the ratchet mechanism may operate similarly to the manner described in conjunction with FIGS. 5-6 above.

A stroke limiter 880 is provided to limit the stroke of piston 830 to a known distance. Consequently, indexing member 836 can move a known amount even if the pressure asserted on piston 830 substantially exceeds the indexing pressure. Stroke limiter 880 thus prevents over indexing when the pressure on piston 830 exceeds the indexing pressure. Accordingly, pressure tests can occur at pressures higher than the indexing pressure without prematurely activating the tool.

According to one embodiment, stroke limiter 880 comprises a tubular having a shoulder spaced from a facing shoulder of piston 830 and positioned to abut the facing shoulder when piston 830 has moved a desired distance in the first direction. According to one embodiment, stroke limiter 880 is configured so that indexing member 836 moves between indexing positions that are a single tooth length “L” apart for a predetermined number of cycles. Stroke limiter 880 can be configured, for example, so that the ratchet 832 moves at least the length “L” of the teeth and less than 2 “L”. According to one embodiment, stroke limiter 880 can limit the stroke of ratchet 632 to 1.3-1.5 “L”. In other embodiments, the stroke limiter 880 can allow the stroke to be greater than 2 “L”, but such an embodiment would reduce the number of indexing positions for the same number of teeth and may result in partial indexing.

According to one embodiment, indexing mechanism 810 includes a collet 884 and activation pin 840. In an initial configuration, activation pin 840 is disposed in collet 884 and forces the collet fingers radially outward. Detents, dogs or other features 886 on the collet fingers can be captured in grooves on the inner wall surface of bore 814. The collet 884 can prevent other components of indexing mechanism 810 from shifting in the first direction. In particular, collet 884 can prevent stroke limiter 880 from shifting.

Upon reaching a predetermined number of indexes, indexing mechanism can shift from an indexing configuration to an activation configuration. In response to the next pressure cycle of at least the indexing pressure (or occurrence of other event), piston 830 will push indexing member 836 against activation pin 840 with sufficient force such that activation pin 840 is released from collet 884 and can shift in the first direction. Activation pin 840 may shift a sufficient distance to rupture a seal 883. With activation pin 840 no longer supporting collet 884, the collet fingers can collapse radially inward and collet 884 can shift in the first direction freeing ratchet ring 842 and stroke limiter 880 to shift. A collet lock can be provided to stop collet 884 from shifting beyond a predefined distance. According to one embodiment, a groove 890 defined in the inner surface of bore 814 can capture features 886

With collet 884 unlocked, stroke limiter 880 can shift. Accordingly, piston 830 can continue to translate, actuating further in the activation cycle than in previous indexing cycles. In one embodiment, indexing mechanism 810 is configured so that piston 830 shifts a sufficient distance such that a piston seal 833 can no longer maintain a seal between piston 830 and the inner surface of bore 814. For example, piston 830 may actuate a sufficient distance such that seal 833 enters an area of bore 814 having a larger diameter. With seal 883 ruptured and seal 833 no longer effective, a flow path is established through bore 814 from first end 816 a to second end 816 b. The flow path can be used to connect a high/low pressure source to an area of a tool (e.g., pressure chamber) to activate the tool.

FIG. 21 is a diagrammatic representation of another embodiment of an indexing an indexing device 900 that allows a tool to be pressure tested multiple times at pressures greater than the pressure required to activate the tool is illustrated. The embodiment of FIG. 21 may allow for the use of more solid parts and allow further size reduction.

According to one embodiment, indexing device 900 includes a housing 901 that houses an indexing mechanism 903. Housing 901, in cooperation with components of indexing mechanism 903, define inner surfaces of an indexing mechanism inner bore 904 that extends from a first end 906a to a second end 906b. Housing 901 can take various forms. According to one embodiment, housing 901 may comprise the walls of a sub or other tool in which an indexing mechanism 903 is installed. In other embodiments, indexing device 900 may be formed as a cartridge with an independent housing, such that indexing device 900 with housing 901 can be installed in an opening in a tool.

Indexing mechanism 903 further includes a reciprocating piston 930 that reciprocates in inner bore 904. By relative movement of between piston 930 and housing 901, piston 930 can advance indexing member 936 in a first direction. The end of indexing member 936 can comprise an activating pin 940. Activating pin 940 may shift through end sub 987 to puncture a rupture disk, remove a plug, trigger an electronic component, detonate a charge or otherwise cause a tool to change state such that the tool activates. According to one embodiment, piston 930 can advance indexing member 936 a predefined amount to a new indexing position each time piston 930 actuates sufficiently in the first direction. Thus, piston can be actuated a number of times before activating pin 940 pierces a seal or otherwise activates a tool.

In one embodiment, piston 930 actuates responsive to hydraulic or mechanical pressure. If at least an indexing pressure is applied, piston 930 actuates in a first direction to move indexing member 936 to a new indexing position, but does not return indexing member 936 to the previous indexing position on the return stroke. Through multiple pressure cycles at or above the indexing pressure, indexing member 936 can be moved in the first direction until it pushes activating pin 940 to activate the tool. Indexing mechanism 903 can be configured such that the pressure asserted on piston 930 in a cycle may exceed the indexing pressure without over indexing. Consequently, a tool can be pressure tested multiple times at pressures above the indexing pressure without being activated. After pressure testing, pressure cycles can be used to complete any remaining indexing cycles to activate the tool.

Piston 930 may include a first piston face 962 and a second piston face 964. By creating a differential pressure across a piston seal, piston 930 may actuate in the first direction. According to one embodiment, a second piston face 964 is exposed to an atmospheric chamber 966 (or other reference pressure) and piston face 962 is exposed to tubing pressure (or other pressure source) to create a pressure differential across piston 930. A biasing member may bias piston 930 in the second direction such that the pressure on piston faces 962 must reach a threshold indexing pressure to actuate piston 930 a sufficient distance to index indexing member 936. In the embodiment depicted, a compression spring 970 (e.g., a Bellville spring or other suitable spring) is provided in atmospheric chamber 966 that biases piston 930 to a starting or non-actuated position.

A hydrostatic preloader 924 can be provided to compensate for anticipated hydrostatic pressure such that a threshold amount of applied pressure is required in the tubing string to actuate piston 930 and index indexing member 936. Hydrostatic preloader 924 can set the initial compression in spring 970 such that piston 930 will not actuate due to anticipated hydrostatic pressure but will instead require a threshold pressure above hydrostatic to actuate. In the embodiment illustrated, hydrostatic preloader 924 comprises a tubular that can be threaded into outer housing 901 to a selected depth to push on shoulder 983 of piston 930 and compress spring 970 a desired amount to preload spring 970. Other mechanisms can also be used to preload spring 970.

Piston 930 includes a ratchet 932 that has an indexing profile 934 defined on its outer surface. Ratchet 932 can reciprocate in a ratchet portion of inner bore 904. Furthermore, indexing mechanism 903 can include a ratchet portion 933 disposed in inner bore 904 that has an indexing profile 928 disposed on portion of an inner surface. Indexing member 936, according to one embodiment, comprises a rack or other ratchet structure that has a surface facing indexing profile 928 and indexing profile 934. A first portion of indexing member 936 includes an indexing profile 938 to selectively engage indexing profile 928 and a second portion includes an indexing profile 939 to selectively engage indexing profile 934. Indexing profiles 938 and 939 may be disposed on the same side of indexing member 936. The indexing profiles 928, 938, 934, 939 can be configured so that indexing member 936 moves with ratchet 932 when ratchet 932 moves in the first direction, but does not move to its previous position when ratchet 932 moves in the second direction. Consequently, by relative movement of between piston 930 and housing 901, indexing member 936 moves incrementally in a first direction with each stroke of ratchet 932 in the first direction but does not move back with ratchet 932 on the return stroke.

A stroke limiter 980 is provided to limit the stroke of piston 930 to a known distance. Consequently, indexing member 636 can move a known amount even if the pressure asserted on piston 630 substantially exceeds the indexing pressure. Stroke limiter 980 thus prevents over indexing when the pressure on piston 930 exceeds the indexing pressure. Accordingly, pressure tests can occur at pressures higher than the indexing pressure without prematurely activating the tool.

According to one embodiment, stroke limiter 980 comprises a shoulder 982 spaced from a facing shoulder 984 and positioned to abut facing shoulder 984 when piston 930 has moved a desired distance in the first direction. According to one embodiment, stroke limiter 980 is configured so that indexing member 936 moves between indexing positions that are a single tooth length “L” apart for a predetermined number of cycles. Stroke limiter 980 can be configured, for example, so that the ratchet 932 moves at least the length “L” of the teeth and less than 2 “L”. In accordance with one embodiment, stroke limiter 980 can limit the stroke of ratchet 932 to 1.3-1.5 “L”. In other embodiments, the stroke limiter 980 can allow the stroke to be greater than 2 L, but such an embodiment would reduce the number of indexing positions for the same number of teeth and may result in partial indexing.

FIG. 22 is a diagrammatic representation of another embodiment of an indexing an indexing device 1000 that allows a tool to be pressure tested multiple times at pressures greater than the pressure required to activate the tool is illustrated. According to one embodiment, indexing device 1000 includes a housing 1001 that houses an indexing mechanism 1003. Housing 1001, in cooperation with components of indexing mechanism 1003, define inner surfaces of an indexing mechanism inner bore 1004. Housing 1001 can take various forms. According to one embodiment, housing 1001 may comprise the walls of a sub or other tool in which an indexing mechanism 1003 is installed. In other embodiments, indexing device 1000 may be formed as a cartridge with an independent housing, such that indexing device 1000 with housing 1001 can be installed in an opening in a tool.

Indexing mechanism 1003 further includes a reciprocating piston 1030 that reciprocates in inner bore 1004. A portion of piston 1030 is disposed in a pressure release sleeve 1031. A piston seal 1033 is provided between the outer surface of piston 1030 and an inner surface of release sleeve 1031. A sleeve seal 1034 is provided between the outer surface of sleeve 1031 and the inner surface of bore 1004. Piston 1030 carries a first ratchet ring 1100 having an outer surface with an indexing profile 1102. Piston 1030 reciprocates through an outer ratchet ring 1110 that has an indexing profile 1112 defined on an inner surface. According to one embodiment, both ratchet rings 1100, 1110 are c-rings.

Ratchet ring 1110 may have an outer profile that prevents movement in a first direction, but not the second direction. Moreover, indexing profiles 1102 and 1112 are configured such that first ratchet ring 1100 can move relative to outer ratchet ring 1110 when piston 1030 carries first ratchet ring 1100 in the first direction. Indexing profiles 1102 and 1112 are configured such that first ratchet ring 1100 cannot move relative to outer ratchet ring 1110 when piston 1030 carries first ratchet ring 1100 in the second direction. Consequently, outer ratchet ring 1110 and sleeve 1031 will move in the second direction with piston 1030.

In one embodiment, piston 1030 actuates responsive to hydraulic or mechanical pressure. If at least an indexing pressure is asserted on piston face 1032, piston 1030 can move ratchet ring 1100 to a new indexing position relate to outer ratchet ring 1110. Thus, at the end of the stroke in the first direction, first ratchet ring 1100 will have indexed relative outer ratchet ring 1110. When the pressure applied to piston face 1032 decreases, a biasing member (not shown) in an atmospheric chamber 1066 (or other reference pressure chamber) can shift piston in the second direction, causing inner ratchet ring 1100, outer ratchet ring 1110 and sleeve 1031 to travel in the second direction.

At the end of each cycle, sleeve 1031 will have moved in the second direction relative to piston 1030 and seals 1033 will have moved relatively closer to area 1037 of sleeve 1031. Area 1037 has an increased diameter such that a seal cannot be maintained between piston 1030 and sleeve 1031. Sleeve 1031 can index in the second direction relative to piston 1030 a predetermined number of times until the piston seal cannot be maintained or sleeve 1031. Embodiments of indexing device 1000 may be used, for example, to release collets and release sliding sleeves.

FIG. 23 is a diagrammatic representation of another embodiment of an indexing mechanism 1200. Indexing mechanism comprises a tubular housing 1202 defining a bore with an inner wall surface having a first indexing profile 1204. A piston 1206 can reciprocating in the inner bore. An outer surface of piston 1206 can have a second indexing profile 1208.

Indexing member 1210 is disposed between piston 1206 and housing 1202. Indexing member 1210, according to one embodiment, comprises a flexible c-ring, lock ring or other structure that has an outer surface facing the inner wall surface housing 1202 and an inner surface facing piston 1206. The outer surface of indexing member 1210 includes an indexing profile 1214 to selectively engage indexing profile 1204 and the inner surface of indexing member 1210 includes an indexing profile 1218 to selectively engage indexing profile 1208.

The indexing profiles 1204, 1214, 1208, 1218 can be configured so that indexing member 1210 moves with piston 1206 when ratchet piston 1206 moves in the first direction, but does not move with piston 1206 when piston 1206 moves in the second direction. Consequently, by relative movement of between piston 1206 and housing 1202, indexing member 1210 moves incrementally in a first direction with each stroke of piston 1206 in the first direction but does not move back with piston 1206 on the return stroke. Indexing mechanism 1200 can be configured such that indexing member 1210 activates a tool after a predetermined number of indexes.

In one embodiment, piston 1206 actuates responsive to hydraulic or mechanical pressure. According to one embodiment, piston 1206 may include a first piston face 1220 that is exposed to a pressure source and second piston face 1222 that is exposed to a reference pressure. If at least an indexing pressure is applied to piston face 1220, piston 1206 actuates in a first direction to move indexing member 1210 to a new indexing position, but does not return indexing member 1210 to the previous indexing position on the return stroke. Through multiple pressure cycles at or above the indexing pressure, indexing member 1210 can be moved in the first direction until it reaches a point where it activates a tool. Indexing mechanism 1200 can be configured such that the pressure asserted on piston 1206 in a cycle may exceed the indexing pressure without over indexing. Consequently, a tool can be pressure tested multiple times at pressures above the indexing pressure without being activated. After pressure testing, pressure cycles can be used to complete any remaining indexing cycles to activate the tool. A stroke limiter can be provided to limit the stroke of piston 1206.

In the embodiment of FIG. 23, piston 1206 may be an internal sleeve of a tool. In accordance with one embodiment, piston 1206 may include a ball seat configured to catch a ball and to generate a piston force across the seat to actuate piston 1206.

Embodiments described herein can be used to activate a variety of wellbore tools including, but not limited to, well treatment tools, packers, perforators or other tools. Typically, a wellbore tool has a tubular housing, which, having a tubular form, can pass readily through the wellbore as drilled. Also, tubular forms can be connected by threading into assembled tools or strings deployable into a well. The tool may be run with the tubing string into a well for temporary use or may be installed in a well for longer term use or reuse. In general, the housing includes an upper end, a lower end and a wall defined between an inner surface and outer surface, with the inner surface defining a tool bore. Moreover, a wellbore tool may have tool mechanism that is responsive to fluid pressure.

The wellbore tool may be a packer, an anchor, a ported tool, etc. The form of the wellbore tool is determined by its tool mechanism. For example, a packer includes a tool mechanism including a packing mechanism with at least a set and an unset position, the packing mechanism may include an annular packing element, one or more compression rings, etc. The tool mechanism of an anchor includes an anchoring mechanism including at least a set and an unset position, the anchoring mechanism may include a plurality of slips, a slip expander, etc. A ported tool intended for fluid circulation between the tubing string inner bore and the outer surface of the tool includes a port and the tool mechanism includes a closure for the port configurable to open and close the port. The closure may be a burst plug, a sliding sleeve, a pocket plug, etc.

An indexing mechanism can be operatively coupled to the tool mechanism. The indexing mechanism can be responsive to pressure cycles (such as tubing pressure cycles) of at least an indexing pressure to index. The indexing mechanism can be set up to activate the tool mechanism after a preset number of indexes. The indexing mechanism may be configured to activate a variety of devices including, but not limited to: sleeves; barrier valves; packers; tubing testers; explosive devices such as a firing head or a peanut charge (to replace a rupture disc and to allow much higher pressure ratings); selective ICD's (inflow control devices), well screens, and other devices.

As the skilled artisan will appreciate, embodiments of indexing mechanism discussed herein may be used with a variety of opening assemblies. For example, an indexing mechanism can be configured to activate a sliding sleeve by exposing a sliding sleeve (or other piston) to tubing pressure such that a pressure differential between the tubing pressure and atmospheric chamber causes the sliding sleeve (or other piston) to actuate to open

In operation, a wellbore tool can be provided with an indexing mechanism that indexes responsive to pressure cycles of at least an indexing pressure. The indexing mechanism can be configured to have an indexing pressure that accounts for the anticipated hydrostatic pressure at the wellbore location at which the wellbore tool will be installed. The indexing pressure can be set above the anticipated hydrostatic pressure so that the hydrostatic pressure does not cycle the indexing mechanism. In one embodiment, the indexing pressure can be set by preloading a spring or other biasing member a desired amount. The indexing mechanism can be configured to activate the wellbore tool after a preset number of pressure applications at surface followed by bleeding off of the applied pressure.

After the wellbore tool is installed in the wellbore as part of a tubing string, a pressure test can be conducted in the tubing string. The pressure test can include applying pressure at surface and bleeding off the applied pressure to pressure cycle the wellbore tool. The tubing string can be pressured up in a cycle so that the pressure at the wellbore tool is at least the indexing pressure. According to one embodiment, cycling the pressure in the wellbore above the indexing pressure can advance a linear index counter in the indexing mechanism. Hydraulic activation of the tool mechanism of the wellbore tool can be prevented by operation of the indexing mechanism for a number of cycles corresponding to a preset number of indexes.

If, after pressure testing, there are remaining indexing cycles, a minimum pressure to reach the indexing pressure can be cycled to drive the indexing mechanism to complete the remaining indexing cycles and activate the tool. The pressure cycles used to complete the remaining indexing cycles and activate the tool can be done at the indexing pressure or activation pressure (if different than the indexing pressure), which may be lower than the pressure test pressure, though higher pressures may be used.

According to one embodiment, an indexing mechanism can be coupled to or incorporated to a toe port tool. The indexing mechanism can be set up to activate the toe port tool only after a preset number of indexes have occurred. The toe port tool can be pressure tested for a number of pressure cycles using pressures that exceed the indexing pressure. If, after pressure testing, there are remaining indexing cycles, the minimum pressure to reach the indexing pressure can be applied to complete the remaining indexing cycles and activate the tool. According to one embodiment, the indexing mechanism can rupture a seal to expose a piston face of the toe port's sliding sleeve to tubing pressure, thereby causing the sliding sleeve to actuate.

As can be understood from the foregoing, indexing mechanisms are provided that, after a preset number of indexes and when incorporated in a tool, can activate the tool, which changes the state of the tool. The indexing mechanism can be incorporated in an integral way in the tool or can be incorporated by a separate connection by means of a control line, electrical cable or other connection.

Indexing mechanism described herein can have a simple design that reduces the overall diameter and thickness of indexing components. The small diameter can result in a high pressure rating for the indexing mechanism. Embodiments described herein can provide small diameter linear indexers that can be integrated into small diameter holes in the walls of tubulars or elsewhere in tools. Indexing mechanism can be run integral with the tool. For example, the indexing mechanism may be disposed in the walls of a tool. An indexing system can be made small enough to allow a plurality of indexing systems to mount in parallel and/or in series, creating redundancy and flexibility. Thus, a toe port tool (or other tool) can be provided with redundancy. Embodiments of indexing mechanisms described herein can also be run in as a side mounted device that can be used to activate sleeves, packers and other tools.

Indexing mechanisms can include stroke limiters to limit indexing length. The short indexing length (stroke) ensures that relative movement within the indexing mechanism is limited and significantly reduced over J-type indexing mechanisms. This may be useful, as well, to reduce the length of the tool. A typical indexing length is 1 inch, but smaller or larger lengths are possible. Moreover, indexing mechanisms according to the present disclosure can incorporate a spring or other energy source in combination with a predefined stroke length. Indexing mechanisms can be set up to only index within a preset operating window that can prevent unintended indexing and allows for accurate cycle counting.

Indexing mechanisms may maintain an atmospheric chamber or other reference preference chamber with a minimal amount of seals, in some cases with only two or three seals and with one of those seals being a rupture disk or the like that is meant to be ruptured. The seals can be relatively small which increases reliability.

Furthermore, various embodiments of indexing mechanisms described herein can be easily reconfigured to add more index cycles. Using FIG. 1 as an example, the indexing mechanism 103 may be lengthened and additional ratchet rings 135 added to increase index cycles.

As discussed above, embodiments described herein may be used in toe port tools. Conventionally, toe port tools are located more than 100 ft from the toe. However, embodiments of indexing mechanisms described herein may be incorporated in toe port tools located very close to the end of the toe (within 100 ft. and in some cases within 20 ft.). FIG. 24, for example, is a diagrammatic representation of a toe portion of a tubing string 1400 having a float shoe 1402, a testable toe port tool 1410 and a bypass sub 1420 located upwell of toe port tool 1410. String 1400 may include other components such as packers, a float collar and other tool. Testable toe port tool 1410 may incorporate indexing mechanisms as discussed above. By moving the testable toe port tool 1410 near to the vicinity of the toe of the well, well treatment can take place at the toe.

According to one embodiment, toe port tool 1410 is located close to the toe of the well so that no tool (balls, shifting tools, etc.) have to pass through toe port tool 1410. This can allow the inner diameter of the toe port tool 1410 to be reduced, providing thicker sidewalls. By way of example, but not limitation, for a tool having a 5.625 inch OD and 3.75 inch ID, the ID may be decreased to 1.25-1.5 inch ID, increasing sidewall thickness by more than 2 inches. The thicker sidewalls provide higher pressure ratings for the atmospheric chambers of the indexing mechanisms. Moreover, thicker sidewalls may also allow atmospheric pressure chambers to be incorporated in a sliding sleeve mechanism even at higher temperature/pressure applications.

According to one embodiment, after the tubing string is run in, the tubing string may be cemented. As is known in the art, a cementing plug may be run through a tubing string after the cement and before the cement has had time to set. The cementing plug may be used, for example, to clean the tubing string of cement. According to one embodiment, a displacement procedure can be run to place a water spacer ahead of the cementing plug before the cement sets to create to displace cement 1440 from around the toe port tool 1410 and create an area of water 1430. A water space may also be run behind the cementing plug. According to one embodiment, the cementing will land at bypass sub 1420. Bypass sub 1420 can allow pressure and fluid to move past the cementing plug to access toe port tool 1410 so that cement 1440 can continue to be displaced and the toe port tool 1410 can be pressure tested and activated.

Reference throughout this specification to “one embodiment”, “an embodiment”, or “a specific embodiment” or similar terminology means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment and may not necessarily be present in all embodiments. Thus, respective appearances of the phrases “in one embodiment”, “in an embodiment”, or “in a specific embodiment” or similar terminology in various places throughout this specification are not necessarily referring to the same embodiment. Furthermore, the particular features, structures, or characteristics of any particular embodiment may be combined in any suitable manner with one or more other embodiments. It is to be understood that other variations and modifications of the embodiments described and illustrated herein are possible in light of the teachings herein and are to be considered as part of the spirit and scope of the invention.

In the description herein, numerous specific details are provided, such as examples of components and/or methods, to provide a thorough understanding of embodiments of the invention. One skilled in the relevant art will recognize, however, that an embodiment may be able to be practiced without one or more of the specific details, or with other apparatus, systems, assemblies, methods, components, materials, parts, and/or the like. In other instances, well-known structures, components, systems, materials, or operations are not specifically shown or described in detail to avoid obscuring aspects of embodiments of the invention. While the invention may be illustrated by using a particular embodiment, this is not and does not limit the invention to any particular embodiment and a person of ordinary skill in the art will recognize that additional embodiments are readily understandable and are a part of this invention.

It will also be appreciated that one or more of the elements depicted in the drawings/figures can also be implemented in a more separated or integrated manner, or even removed or rendered as inoperable in certain cases, as is useful in accordance with a particular application. Additionally, any signal arrows in the drawings/figures should be considered only as exemplary, and not limiting, unless otherwise specifically noted.

As used herein, the terms “comprises,” “comprising,” “includes,” “including,” “has,” “having,” or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, product, article, or apparatus that comprises a list of elements is not necessarily limited only those elements but may include other elements not expressly listed or inherent to such a process, product, article, or apparatus.

Furthermore, the term “or” as used herein is generally intended to mean “and/or” unless otherwise indicated. For example, a condition A or B is satisfied by any one of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present). As used herein, including the claims that follow, a term preceded by “a” or “an” (and “the” when antecedent basis is “a” or “an”) includes both singular and plural of such term, unless clearly indicated within the claim otherwise (i.e., that the reference “a” or “an” clearly indicates only the singular or only the plural). Also, as used in the description herein and throughout the claims that follow, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise. 

1. A wellbore tool comprising: a tubular housing having an inner surface and an outer surface, the inner surface defining a central bore; a tool mechanism responsive to hydraulic pressure; and an indexing mechanism that indexes responsive to tubing pressure cycles of at least an indexing pressure, the indexing mechanism having an adjustable indexing pressure and configured to activate the tool mechanism after a preset number of indexes, wherein the wellbore tool is pressure testable at pressures above an activation pressure without activating the tool mechanism for a number of tubing pressure test cycles.
 2. The wellbore tool of claim 1, wherein the indexing pressure is adjustable such that the indexing pressure is defined for the number of tubing pressure test cycles.
 3. The wellbore tool of claim 1, wherein the indexing mechanism comprises a biasing member to bias the indexing mechanism against pressure applied to the indexing mechanism and a hydrostatic preloader adjustable to preload the biasing member to adjust the adjustable indexing pressure.
 4. The wellbore tool of claim 3, wherein the indexing mechanism comprises: a ratchet mechanism defining a plurality of indexing positions and comprising a movable ratchet and an indexing member translatable through the plurality of indexing positions from an initial indexing position to a final indexing position; and an indexing piston adapted to move the movable ratchet to incrementally advance the indexing member in a first direction; and wherein the biasing member biases the indexing piston in a second direction. 5-28. (canceled)
 29. A wellbore tool comprising: a tubular housing having an inner surface and an outer surface, the inner surface defining a central bore; a tool mechanism responsive to hydraulic pressure; and an indexing mechanism that indexes responsive to tubing pressure cycles of at least an indexing pressure, the indexing mechanism configured to activate the tool mechanism after a preset number of indexes, the indexing mechanism comprising an activation mechanism adapted to punch an opening in a device to activate the tool mechanism, wherein the wellbore tool is pressure testable at pressures above an activation pressure without activating the tool mechanism for a number of tubing pressure test cycles.
 30. The wellbore tool of claim 29, wherein the device comprises a rupture disk.
 31. The wellbore tool of claim 29, wherein the activation mechanism further comprises: an activation member movable from an activation member initial position to an activation member second position and wherein the indexing mechanism comprises an indexing piston adapted to drive the activation member to punch the opening in the device.
 32. The wellbore tool of claim 31, wherein the activation mechanism is adapted to open a flow path through the indexing mechanism when activated.
 33. The wellbore tool of claim 32, wherein the indexing mechanism is configured to isolate the tool mechanism from the central bore to prevent the tool mechanism from prematurely activating and to activate the tool mechanism after the preset number of indexes by opening the flow path through the indexing mechanism to fluidly connect the central bore to the tool mechanism. 34-35. (canceled)
 36. The wellbore tool of claim 29, wherein: the indexing mechanism comprises a ratchet mechanism, the ratchet mechanism defining a plurality of indexing positions and comprising a movable ratchet and an indexing member translatable in an indexing mechanism bore through the plurality of indexing positions from an initial indexing position to a final indexing position; and the indexing piston is adapted to move the movable ratchet to incrementally advance the indexing member in a first direction, through a series of pressure responsive actuations, from the initial indexing position to the final indexing position and to push the indexing member against the activation member to shift the activation member from the activation member initial position to the activation member second position.
 37. The wellbore tool of claim 36, wherein: the ratchet mechanism further comprises a first indexing profile disposed on an inner wall surface of an indexing mechanism bore; the movable ratchet comprises a second indexing profile; and the indexing member is disposed between the inner wall surface and the movable ratchet, the indexing member having an outer surface with a third indexing profile selected to engage the first indexing profile and an inner surface with a fourth indexing profile selected to engage the second indexing profile, wherein the first indexing profile, second indexing profile, third indexing profile and fourth indexing profile are selected such that the indexing member is movable with the movable ratchet in the first direction and is stopped against movement with the movable ratchet in a second direction.
 38. The wellbore tool of claim 36, wherein the indexing mechanism comprises a biasing member that biases the indexing piston in a second direction; a stroke limiter to limit an indexing stroke length of the indexing piston; and a hydrostatic preloader settable to preload the biasing member to adjust the indexing pressure.
 39. The wellbore tool of claim 29, wherein the indexing mechanism changes from an indexing configuration to an activation configuration upon reaching the preset number of indexes, wherein in the activation configuration, the indexing mechanism is responsive to the activation pressure to activate the tool mechanism.
 40. The wellbore tool of claim 39, wherein the activation pressure is the same as the indexing pressure.
 41. The wellbore tool of claim 29, wherein the tubular housing has one or more ports through a housing wall that are openable to connect the central bore to the outer surface and wherein the tool mechanism comprises a sliding sleeve slidable from a port closed position blocking the one or more ports to a port open position at least partially retracted from the one or more ports.
 42. The wellbore tool of claim 41, wherein the indexing mechanism is configured to isolate the tool mechanism from the central bore to prevent the tool mechanism from prematurely activating and to activate the tool mechanism to open the sliding sleeve after the preset number of indexes by opening a flow path from the central bore to the tool mechanism. 43-79. (canceled)
 80. A method for actuating a downhole tool, the method comprising: installing a wellbore tool in a wellbore, the wellbore tool comprising an indexing mechanism configured to index pressure cycles of at least an indexing pressure and activate the wellbore tool after a preset number of indexes; conducting one or more pressure tests of the tubing string by applying one or more test pressures to the tubing string such that a tubing pressure at the wellbore tool during the one or more pressure tests is above the indexing pressure for the wellbore tool; and after completion of the one or more pressure tests, applying pressure to the tubing string to complete remaining index cycles and cause the indexing mechanism to punch an opening in a device to activate the wellbore tool, wherein a pressure applied to the tubing string to cause the indexing mechanism to punch the opening in the device is lower than the one or more test pressures.
 81. The method of claim 80, further comprising configuring the indexing mechanism prior to installing the wellbore tool such that the indexing pressure is at least a hydrostatic pressure at a location in the wellbore where wellbore tool is to be installed.
 82. The method of claim 80, wherein the device comprises a rupture disk. 83-88. (canceled) 